Former Toro Rosso driver Jaime Alguersuari has insisted that this weekend's Singapore Grand Prix will be the 'toughest' on the calendar this season.

The Spaniard, now working as a co-commentator for BBC Five Live after losing his drive at the end of the 2011 season, competed in Singapore three times himself while with the Italian team, taking a best finish of twelfth in 2010.

Writing in his BBC Sport column, Alguersuari insisted that the race was one of the most challenging that drivers will face with plenty of opportunity for time to be won and lost over the course of a lap.

"The layout does not look much on a track map, but actually it is very technical and hugely physical for the driver," he wrote."It is probably the toughest race on the calendar for a number of reasons. It is very warm in Singapore, often 30C even at night, it's very humid being in the tropics and it feels as if there is not really any air. On top of all that, it is the longest race of the year - nearly two hours.

"The walls are close and you see all the skyscrapers as you go around the track; it is just a beautiful experience. To get the best out of the track you have to ride all the kerbs at the corners, nearly all of which are quite slow, so traction and braking stability are crucial. The car is loaded with downforce, because the straights are not that long, and there are places to overtake.

"The corners are all quite slow and are quite different from what you might experience at other tracks. There are a lot of slow-speed corners and hairpins, with big braking, but some of them are quite special. In some ways, it is like a rally course, with so many slow-speed corners and so many places to lose and gain time. It is a fantastic feeling."