There are serious doubts whether qualifying for the Japanese Grand Prix will go ahead on Saturday after heavy rain fell throughout final practice.
Only two drivers completed timed laps as 'rivers' of water flowed across the Japanese circuit.
McLaren's Lewis Hamilton described conditions as "unbelievable".
"It is pretty much impossible to drive out here," Hamilton told his team during an exploratory lap shortly before the end of the allotted hour.
Qualifying is due to start at 0600 BST. If it is postponed, among the options are to run it on the morning of the race, or even to form the grid in world championship order.
However with the forecast for Suzuka on Sunday being for dry conditions throughout the day, moving qualifying to start at 10.00 local time on Sunday (0200 BST) is understood to be the likeliest outcome.
Only Timo Glock and Jaime Alguersuari recorded timed laps in final practice, with every driver reporting the cars were aqua-planing on their installation laps.
Mercedes team principal Ross Brawn told BBC Radio 5 live he did not believe qualifying should take place if conditions remained the same.
"We don't think qualifying will start if it's this bad and we are not sure of the merits of running in these conditions," he said.
"It will be too dangerous. When the cars run they will not clear the water. I will be disappointed if we start qualifying in these conditions. We could have the grid decided by championship order, that's happened before, or qualifying could take place on Sunday morning."
More to follow.
Potenshöjande medel - potenshöjande medel