Russian GP: Track sweeper caused diesel spill that hit F1 practice

It has emerged that the vehicle spilled the fuel while it cleaned the circuit on Thursday evening ahead of Friday practice.

The problem was not spotted until 0830 local time on Friday, 90 minutes before the first session was due to start.

An absorbent was used to soak up the diesel before pressure washers were drafted in to blast the spill, which affected Turns 7, 8, 9 and 10, off the track.

It meant drivers could not take advantage of what became the only dry running of the day - as rain washed out practice two - to collect qualifying and race data.

"Unfortunately the only dry session was wiped away because of that," said Ferrari's Kimi Raikkonen.

"They had to wash the circuit, it was a bit useless but what can we do? It's one of those things.

"It's not ideal but it's the same for everyone. We'd rather do the practice in good conditions. We'll try to make the best out of tomorrow."

Red Bull's Daniil Kvyat added: "In Singapore there was a drunk man on track, so these things can happen anywhere.

"It spoiled FP1 because it was the only dry session and it would have helped the teams to get references for tomorrow.

"But everyone was in the same position and everyone will have to work harder tomorrow."

Lotus driver Pastor Maldonado described the affected parts of the track as like driving on ice.

"It's quite frustrating," said Maldonado. "We were ready to do everything in FP1 because the weather forecast was bad for the afternoon.

"I've not seen something like this before, maybe when an engine or gearbox breaks, but never as big.

"We were going very slow and the cars were sliding everywhere. It was like ice, especially in Turn 8 and 9."

Sauber's Felipe Nasr added: "It was very slippery out there so it was difficult to keep the car straight in the places where diesel leaked."