UPDATED: Lewis Hamilton believes that raising tyre pressures on safety ngrounds in the wake of the accidents at Spa-Francorchamps could be 'a disaster' for F1 in Italy this weekend. 
Felipe Massa and Valtteri Bottas will remain with Williams Martini Racing for the 2016 Formula 1 season, it is confirmed.
Claire Williams is delighted Valtteri Bottas will enter into a fourth season with Williams next year as she sets a target of race wins. 
Felipe Massa says he is lucky to have strong support at Monza after his time with Ferrari and feels Williams has the potential to fight for podiums
The first Williams team appeared in Formula One under the banner of Frank Williams Racing Cars, after the business, which introduced Frank Williams to racing.
Perennially underfunded, the team initially ran Brabhams and de Tomasos for family friend Piers Courage but, when the brewery heir was killed at Zandvoort in 1970, Williams reverted to running pay drivers to prolong his involvement in the sport.
An ill-fated merger with Canadian oil baron Walter Wolf in 1976 promised much but produced little, and Williams decided to strike out on his own once more. In partnership with emerging designer Patrick Head, he formed Williams Grand Prix Engineering at the end of 1977. With the newly discovered source of Saudi Arabian sponsorship behind them, the compact FW06 chassis and Australian driver Alan Jones, Williams GPE made a solid start in 1978.
The following year, Head brought out the FW07, and its ground effect technology soon brought the team to the front of the grid. A maiden win came courtesy of Clay Regazzoni at Silverstone and was followed by four more for Jones, who came close to winning the team's first title.
The combination went one better in 1980, with Jones taking the Drivers' title and Williams the Constructors' crown. A second Constructors' title followed in '81, but Jones quit the sport after missing out to Nelson Piquet in the Drivers' standings. Nevertheless, Williams continued to feature at the head of the field for some time, with Keke Rosberg taking the title in 1982.
A relatively poor season in 1983 was the precursor to an arrangement with Honda to run the Japanese company's turbo-charged engines. Although 1984 brought little in the way of success, Rosberg and new signing Nigel Mansell won the final three races of 1985 to set up a championship challenge the following year.
As it turned out, however, Williams, Mansell and Piquet lost out to Alain Prost and McLaren following Mansell's famous tyre failure in Adelaide, but a third Constructors' title still came the team's way. The success was made all the more remarkable as it followed the pre-season car crash which left Frank Williams in a wheelchair.
Piquet took the title in 1987 after an acrimonious tussle with Mansell, and Williams sealed its fourth Constructors' success, but the Brazilian followed the supply of Honda engines to Lotus for 1988. McLaren also secured the use of the Japanese units that season, and went on to dominate - winning 15 of the 16 races - in a barren year for Williams, who were left to use Judd power-plants.
The re-entry of Renault in 1989 provided the team with hope of a revival and, although it took several seasons, Williams eventually found themselves back at the front. Wins for team-mates Ricardo Patrese and Thierry Boutsen in the period between 1989 and 1991 preceded the successful return of Mansell, who went on to win a then record nine grands prix in 1992 en route to the Drivers' title.
The 1992 season also started a run of three successive Constructors' crowns for the team, while Alain Prost added a fifth Drivers' title in 1993.
Ayrton Senna - who had his first F1 test with Williams in 1983 - returned to the team in 1994, hoping to add to his championship tally. Tragically, his season was cut short by a fatal accident at Imola, which stunned the whole sport. Team-mate Damon Hill rose to the challenge, however, and pushed Michael Schumacher close for the title, whilst securing another makes crown for Williams.
Hill was rewarded for his persistence by finally taking the title for himself in 1996, despite a concerted effort from rookie team-mate Jacques Villeneuve. The champion was axed at the end of the season, however, following in a long line of Williams champions to have left the team with the coveted number one plate. Villeneuve then stepped up to regain the title for the Grove outfit in 1997, although he literally had to fend off Michael Schumacher at the final round to secure the crown.
Further Constructors' successes in 1996 and '97 followed boosting Williams' record to nine in total.
The 1998 line-up saw Villeneuve and Heinz-Harald Frentzen retained for a second season together, but the FW20 chassis proved to be no match for the resurgent McLaren team. The loss of Renault engines left Williams using customer Mecachrome units until the works BMW deal came into effect in the year 2000, and it was the powerplant, which primarily saw the team suffer its first winless season for many years. Villeneuve took two battling podium finishes in Germany and Hungary, but that was to be the team's lot.
It was all change at Grove for 1999, with both drivers leaving for pastures new, and being replaced by Alex Zanardi and Ralf Schumacher. For the second time in four seasons, Williams had signed the reigning CART champion, with Zanardi returning to grand's prix on the back of two US series crowns. Schumacher moved over from Jordan after two less successful seasons, but dominated proceedings in the team, as Zanardi failed to come to grips with modern grand prix machinery. At the end of the year, the Italian left, pointless, midway through his contract, while Schumacher came close to winning at the Nurburgring and was feted as a star of the season.
The German remained as team leader in 2000, and was joined by British rookie Jenson Button. The 20-year old came to grand's prix after just two seasons out of karts, and brought with him much hype from sections of his native press. BMW also arrived at Grove, pumping money and a new V10 into the team in order to restore it to the top of the pile.
During the 2000 season Button rose to the challenge of Formula One manfully and was often a little too close for comfort to the vastly more experienced Schumacher. Sixth on the grid alongside Michael Schumacher at Silverstone and a fantastic third fastest time at Spa confirmed Button's status as a future champion and there was much consternation when it was announced that he was being loaned to Benetton for the next two seasons in order to make way for Colombian sensation Juan Pablo Montoya.
Montoya's arrival was one of the most anticipated things of the 2001 season, despite Zanardi's disastrous move from Champcars still fresh in the memory. The Colombian did not disappoint, but suffered appalling luck throughout the year.
Retirements in each of the two opening races looked set to be put right by victory in Brazil - only for Jos Verstappen to rear-end the Williams while being lapped! Another failure at Imola meant that it was five rounds before Montoya eventually scored - but when he did, he took second spot in Spain behind Michael Schumacher. Of the five finishes that followed, four were in the points, three on the podium and one on the top step - at Monza - leaving Montoya sixth overall.
By the end of the year, he was overshadowing team-mate Ralf Schumacher on a regular basis, but the German already had three wins under his belt, at Imola, Montreal and Hockenheim. Also thwarted by poor reliability, however, Schumacher could not mount a championship challenge and faded to fourth overall.
The same two drivers remained onboard for 2002 and despite hopes that they might take the battle to Ferrari, Williams ended the year, best of the rest, second in the Constructors' championship, with 92 points.
It was not a great year for Williams, and despite taking thirteen podium finishes, they would win only once, courtesy of Ralf at the Malaysian GP in March.
The only other highlight was Montoya's run of five consecutive pole positions, from the Monte Carlo GP in May to the French GP in July. JPM would also set a then new record for the fastest ever F1 lap, at the Italian GP in September, but the fact remained Ferrari was just light years ahead. All in all, the problem was not so much the BMW engine, reckoned to be one of the best in F1, but rather the FW24 chassis, which was heavily criticised for being the weak link.
For 2003 Williams stuck with the Ralf-Montoya pairing for a third year, and despite a difficult start to the season, the FW25 shone, especially from the Monaco GP onwards.
In total the team scored four wins, and eight further podiums, however despite challenging for both crowns, the squad ended up 'second best', finishing 14 points behind Ferrari in the Constructors', and third and fifth in the Drivers' series, although Montoya had been in with a shout of the Drivers' crown until the penultimate race.
Behind the scenes negotiations with BMW were long, but successful, and the partnership was extended.
Montoya meanwhile decided to leave the team at the end of 2004, signing a deal with McLaren-Mercedes for 2005. Ralf's contract was also not renewed, and in July he signed a three-year deal with Toyota.
2004 was by no means the season Williams had planned then, with both drivers' destined to leave at the end of the year.
The 'eye-catching' FW26, with its tusk nose, proved to be ill-conceived, and was later replaced by a more conservative version. Furthermore while Williams scored points in virtually every race, bar three, they only notched up four podiums, and had to wait until the final grand prix of the year to win, when Montoya, triumphed in Brazil.
There were other dramas as well, most noticeably Ralf's horrific crash at the US Grand Prix, which left him sidelined for six races, where test drivers Marc Gene and Antonio Pizzonia were called upon to fill the void. The team was also disqualified from the Canadian GP for technical irregularities, after finishing second and fourth, another embarrassing moment.
Behind the scenes, technical director, Patrick Head, passed the baton onto Sam Michael, and attempts to sign Jenson Button failed, after the CRB [Contract Recognition Board] ruled in BAR's favour.
In total Williams concluded the season with 88 points, fourth in the constructors' behind Ferrari, BAR and Renault.
In 2005, Mark Webber joined the team, and he was partnered by Nick Heidfeld, following the botched attempt to get Button.
The season though was another disappointing one, with only one real high, when the team finished 2-3 at the Monaco Grand Prix. Although Heidfeld also gave the team two other podium finishes - in Malaysia and at the Nurburgring - that was as good as it got and neither driver managed to win with the uncompetitive FW27.
Indeed the combined performance of Williams and BMW was so bad that their relationship continued to deteriorate, the two eventually opting to go their separate ways at the end of the year, with the latter taking over the Sauber team.
In total, Williams concluded the season with 66 points, fifth in the constructors' behind the likes of Renault, McLaren, Ferrari and Toyota, while Webber and Heidfeld took tenth and eleventh in the drivers' standings, although the latter missed the final five races due to injury.
After failing to reach the success either party wished for, the relationship with BMW was dissolved ahead of schedule, leaving Williams to use Cosworth engines in 2006. The British engine builder had also found itself without a team to work with following Red Bull Racing's defection to Ferrari, and the pair reunited for the first time since their successful early '80 partnership.
Williams also switched to Bridgestone tyres, and its driver line-up changed. Webber stayed on, but Heidfeld left with BMW, the second seat going to Keke Rosberg's son, Nico, following his GP2 title success.
Pre-season testing, however, revealed some disturbing reliability woes that were going a long way to overshadow the ultimate pace of the FW28 and its drivers.
Nonetheless, this seemed to be all forgotten when the season begun in earnest at Bahrain, with Webber qualifying inside the top ten and going on to finish in sixth place. Rosberg, too, made headlines on his debut, spinning down to last place at the first corner, only to redeem himself with a magnificent comeback drive peppered by several impressive overtaking manoeuvres that belied his novice status.
However, qualifying on the second row in Malaysia aside, the encouraging start soon gave way to increasing frustration as those durability concerns began to seep in, with a myriad of mechanical problems eventually limiting both Webber and Rosberg to just three more points finishes between them.
Rather more telling was the tally of 20 retirements out of a combined total of 36 races, a desperate statistic that disguised flashes of speed, most notably at Monaco and Hockenheim, when Webber was in contention for a podium before being forced out.
Having become increasingly vocal about Williams' failings, the Australian announced mid-season that he would be joining Red Bull, and he was replaced for 2007 by test driver Alex Wurz, the Austrian making a full-time race comeback after having spent seven years on the test 'bench'.
Williams also announced another switch of engine supplier, with Cosworth, despite being blameless for most of the retirements, losing out to Toyota.
Having only scored eleven points in '06 and finished eighth in the constructors', Williams had much to prove in 2007 and thankfully the Grove-based concern seemed to bounce back.
There was no wins - nor did any look likely - but the FW29 was pretty competitive in the midfield pack, something that allowed Rosberg and Wurz to notch up 33 points in total - three times as many as the team managed the year before. Consequently Williams finished fourth in the constructors'.
More importantly though the car was reliable and Nico really seemed to find his feet, ending the season ninth in the drivers' championship. He managed seven points' finishes in total, including five in the final seven races, culminating with a fourth place at the season ending, Brazilian GP.
While Rosberg shined though, Wurz ultimately proved a bit disappointing and he scored only 13 points. Furthermore while he made the most of his experience to take third at the Canadian GP and fourth at the Nurburgring, in the end his decision to retire wasn't a surprise, although the fact he opted to do it with only one race left, was somewhat unusual.
Williams managed to hang onto Rosberg for 2008 - despite the German having been targeted by McLaren as a potential replacement for the disaffected Fernando Alonso – and Nico linked up with Toyota protégé Kazuki Nakajima who, having spent a year combining a testing role with a combative season in GP2, was handed the chance to graduate to the top flight.
The FW30, which spent the pre-season bedecked in various liveries celebrating the team’s 30th season and assorted landmarks that would be racked up during it, proved to be a solid, if unspectacular, car, but one that could not cope with the varied venues on the schedule – or the switch of attention to 2009.
Rosberg’s year was similarly one of highs and lows, capped by safety car–assisted podium finishes in Australia and Singapore, but marked by a massive shunt while well-placed in Monaco and his unfortunate involvement in the Hamilton/Raikkonen pit-lane farce while on course for third in Montreal.
Nakajima, having been given a head-start on his F1 career with an early debut at Interlagos ’07 as replacement for the retiring Wurz, produced his best finish in round one, with sixth place in Melbourne, but was then left to battle for scraps in those races where attrition was at its worst. Only Rosberg’s late-season bonus under the lights separated the pair in the championship, however, with Williams being restricted to eighth overall among the constructors.
Little has changed for 2009, with the same two drivers in the hot seat, and talented German Nico Hulkenberg waiting eagerly in the wings. The new rules and cost-cutting proposals, however, give the Grove outfit a rare chance to make up ground on its more monied rivals, and early testing with the FW31 has again shown that the team under Patrick Head can design a competent car.
Rosberg again led the team into 2009, with the FW31 being one of the few cars on the grid at the start of the season to feature a double diffuser. That should have been a factor which allowed Williams to become regular contenders towards the front of the field but, while the car was a regular points finisher, it wasn’t quick enough to finish on the podium. For Rosberg, fourth place in German and Hungary were the highlights but when the season came to an end, so did his time with the team as he moved on to Mercedes for 2010.
Team-mate Nakajima would also depart at the end of the 2009 season, although in the case of the Japanese driver it was a lack of results that would cost him his drive. Although there were high points, such as fifth on the grid at Silverstone, Nakajima failed to score a point all season – making him the only driver to contest the full season not to manage a single point.
For 2010 then it was all change, with a new look driver line-up of Rubens Barrichello and Nico Hulkenberg and a switch from Toyota power to Cosworth after its partnership with the Japanese manufacturer drew to a close.
It would be a steady, if not spectacular season for Barrichello with a number of points finishes – the highlight being fourth place in the European Grand Prix – while 2010 was also the season where he celebrated his 300th F1 race, becoming the first driver to reach the milestone. Although unable to take the team back onto the podium, the veteran Brazilian was retained for a second season.
The same couldn’t be said for rookie team-mate Hulkenberg, who made the move into F1 as GP2 champion and with a big reputation to live up to. While clearly a quick driver, Hulkenberg suffered his fair share of misfortune and also made his fair share of mistakes, although his showed why he was so highly rated by securing a stunning pole position in Brazil – the first for a Williams driver since 2005. It wasn’t enough however as the German found himself dropped after just one season, with Pastor Maldonado being brought in for the 2011 campaign.
It would however be a season to forget for both Barrichello and Maldonado as Williams endured the worst year in its history.
The FW33 was neither quick or reliable and between them, Barrichello and Maldonado managed just five points to leave the team down in ninth place in the constructors’ championship. Technical director Sam Michael paid the price for the poor form as he left mid-season to be replaced by Mike Coughlan, with the team electing to restructure in the hope of regaining form in 2012.
The new season heralded the return of one of the most successful partnerships in F1 as Williams switched from Cosworth to Renault for its engine supply, while the curtain came down on Barrichello’s long F1 career as he was replaced by fellow Brazilian Bruno Senna.
Having managed just five points all season in 2011, it didn’t take long for Williams to beat that total when Senna took sixth in Malaysia, with Maldonado missing out on strong results in the first two races of the year when an accident in Australia was followed by an engine issue late on at Sepang.
After a solid start to the season in the fly-away events, things took an unexpected turn for the better in Spain, where Maldonado started from pole and then beat home favourite Fernando Alonso to victory – marking the first success for Williams in eight years. However, it was perhaps an indication of what was to come when the team then suffered a fire in its garage while celebrating the success.
Maldonado would fail to score again until the Japanese Grand Prix, throwing away some impressive qualifying results with a number of controversial clashes on track, while Senna would pick up the lower points on a regular basis but paid the price for losing the opening practice session at the majority of the races as the team gave track time to test driver Valtteri Bottas.
Fifth for Maldonado in Abu Dhabi, despite KERS failure, was a prime example of what could have been for the Grove-based team and although 2012 was a massive improvement on 2011, the fact that the team could only finish eighth in the standings despite having a race winning car was something of a disappointment.
For 2013, Williams will aim to show its pace again but add in the consistency that was missing so badly in 2012, with Maldonado returning for a third season and Bottas moving up into the second seat, with the team hoping that the young Finn can produce the goods after impressing in his practice outings.
Daniel Ricciardo admits that Mercedes is probably still out of reach, despite being 'best of the rest' in free practice at the Belgian Grand Prix. 
Nico Rosberg completed a clean sweep of Friday F1 practice at Spa-Francorchamps, but not without another problem as he suffered a high-speed tyre failure. 
Despite losing track time with mechanical issues, Nico Rosberg turns in the fastest FP1 time at Spa-Francorchamps, as Pastor Maldonado crash interrupts session
Valtteri Bottas says the constant rumours and speculation linking him to Ferrari were an 'unnecessary' distraction for himself and Williams. 
Felipe Massa admits to hoping that Williams will retain its current F1 driver line-up now that speculation over Kimi Raikkonen's Ferrari futue has been settled.