Calls for Alistair Darling to slap a multi-billion pound windfall tax on the oil companies intensified last night after BP posted bumper profits of £4.3bn in just three months - or £45m a day - on the back of soaring oil and gas prices.

Jim Devine, the Labour MP for Livingston, branded the profits "obscene" and called on the Chancellor to act either by imposing a windfall tax or by forcing oil companies to cut petrol pump prices.

Mr Darling is due in the autumn to produce an "economic plan" to try to avoid Britain plunging into a recession.

Yesterday, BP posted half-year profits of £6.75bn, 23% ahead of the previous year, as the oil giant reaped the benefit of record fuel prices. Between April and June, the company made underlying profits of £4.3bn, almost £2m an hour and 56% ahead of the same period last year.

The results, which shattered City expectations, were driven by soaring crude oil, which finished June at nearly $144 a barrel.

However, the AA pointed out that motorists suffered an average 10p rise in the price of a litre of petrol to 118.2p over the period with average diesel prices more than 14p up to 131.6p.

While the oil firm will plough around £11bn back into capital expenditure and exploring for oil and gas this year, the profits will only add to anger among hauliers and drivers over costs.

Last night, Mr Devine told The Herald: "These profits are quite frankly obscene. BP is ripping off the motorists of Britain and that is why I have today written to the Chancellor demanding that action is taken on one of two fronts: either the Labour Government should be implementing a windfall tax on companies such as BP or we should be forcing BP to reduce prices at the pump."

BP, however, hit back, insisting that it made less than 1p in profit on every litre of petrol it sold at its 1300 filling stations across the UK.

Alex Salmond yesterday rejected calls for a windfall tax on oil companies but warned Mr Darling that unless the Treasury spent some of its own windfall on alleviating fuel costs he risked recession.

The First Minister, said the UK Government had ruled out any fresh windfall tax on oil companies after the last Corporation Tax hike and going back on that could risk inward investment. "The windfall we should be aiming for is the windfall for Alistair Darling which this year has seen an additional £6000m over and above what he projected in March," he said.

"There is a risk of us getting dragged into recession, therefore it is exactly the right time to inject demand into the economy by helping with energy costs for consumers."