With most of the GP2 cars lining up along pit lane queuing for the green light to start the GP2 practice session in Monaco, it was clear from the start that traffic was likely to be a major factor in proceedings.

Sure enough, a number of the top drivers - notably Caterham's Giedo van der Garde - had one or even two consecutive purple sectors on the timesheets, only to lose it in the third when they came up on the back of slow traffic preparing for their own flying laps next time around. Fortunately there was no repeat of the 'parking' in Rascasse that so incensed race stewards in 2011, and there were no actual rear-end collisions during the session - although Barwa Addax's Johnny Cecotto Jr. came perilously close to impacting the backside of a dawdling Arden in the hands of Simon Trummer mid-session.

Esteban Guti?rrez's practice session came to a very early half when he triggered the first local yellows of the day by getting unbalanced over the kerbing at St Devote and ended up heading into a crunching impact with the Armco barrier. His Lotus GP team mate James Calado would come close to repeating the mistake later in the session.

One of the two local drivers - Stephane Richelmi in the Trident Racing car - was one of the first to set a fast time as the track cleaned up and started acquiring some grip, going second with a lap of 1:25.704s around four tenths behind Arden's Luiz Razia. But these were just the early gambits, and the times would quickly tumble from there - Razia promptly improved to 1:23.792s.

By the time the session was 11 minutes old, Razia had been displaced from the top spot by Max Chilton going three hundredths faster in the Carlin car. Johnny Cecotto Jr. had popped up into third place of the timings ahead of Davide Valsecchi (DAMS), with Marcus Ericsson (iSport) and Fabio Leimer (Racing Engineering) also looking pacey in the top six.

Another local yellow came out during the mid-session lull when Giancarlo Serenelli lost the back end of the Venezuela GP Lazarus through Rascasse and stalled the car; but once the flags were withdrawn, Barwa Addax duo Johnny Cecotto and Josef Kral and Johnny Cecotto immediately put in fliers to go briefly one-two, with Cecotto setting a new target laptime of 1:22.835s.

However, having set their early laps on the prime (soft) Pirelli tyres, drivers were starting to look at giving the option (super soft) tyres a workout for the second half of the session. Jolyon Palmer was the first man out on the red tyres with a little over ten minutes remaining on the clock. But they took a while to find their grip, and in the meantime Giedo van der Garde finally found a clear lap to go top of the pile with a lap of 1:22.757, with Valsecchi immediately improving to second leaving Palmer to settle for third.

Unfortunately van der Garde wouldn't have a chance to try to defend his provisional pole: he ran wide out of Rascasse and gave the Armco the lightest of love taps with his front wing, unfortunately stalling the car in the process. Josef Kral would also come a cropper on this next push for the top time, spinning right round on the exit of the Swimming Pool and giving the lightest of taps with his front wing on the barrier. It looked as though Kral had kept the engine running, but he then stalled it when trying to turn the car back around and had to sit in the middle of the track awaiting the ignominy of the Monaco hoist.

With less than two minutes to go at this point, it seemed as through Kral's local yellow would persist to the end and ruin the final flying laps of those still pushing out on track. But in another demonstration of the near-miraculous abilities of the Monaco track workers the Addax was plucked away in time for Davide Valsecchi (still on prime tyres) to set a new fastest time of 1:22.745s for the session that was immediately blown away by Kral's team mate Cecotto (now on the super softs) going 1:22.075s as the chequered flag came out.

It all sets up an exciting prospect for the afternoon qualifying session starting 4.55pm (3.55pm BST), in which traffic will be less of a problem after the decision was taken to split the half our into two 14 minute groups. A ballot decided that the first group out would consist of the even-numbered cars (including practice spinners Kral, van der Garde and Guti?rrez) and the second group with the potential advantage of extra grip on the track would be the odd-numbers cars (including Cecotto, Valsecchi and Razia).

Full practice times available.