Mat Coch writes:

Three teams fell foul of curfew restrictions on Saturday morning, with marketing staff from Red Bull, Mercedes and Virgin all within the circuit during the enforced lock down.

Teams are allowed four exceptions to the curfew per season, Red Bull having now used three, Virgin two and this being the first such instance for Mercedes.

According to the regulations staff associated with the operation of the car should have left the circuit by 09:30 on Saturday morning, and not returned until 16:00 that afternoon.

Speculation within the paddock on Saturday had some sceptics suggesting that all was not as it appeared, and that 'marketing' was being used as an excuse to work on the cars, under the guise of adding sponsors logos to the car. It led one observer to suggest that it wouldn't be long before teams begin hiring marketing staff with engineering degrees.

More likely however is that teams were caught out by the notoriously difficult timetable the Singapore Grand Prix keeps. With the working day beginning in the early afternoon and carrying through ito the small hours of the following morning, keeping to the right time is easier said than done. It was a point proved yesterday when Franz Tost arrived too early, resulting in the same curfew exception notice for Toro Rosso.