Motorists are struggling with the fastest rises in diesel prices for a decade as the fuel crisis worsens.

With oil soaring in a trading frenzy to a new high of nearly $130 a barrel last night, the stock market fell and Chancellor Alistair Darling pledged international action to beg oil producers to release more supplies.

Diesel is rising even faster than petrol and an increase to an average of 125.4p a litre - or £5.70 a gallon - is crippling motorists and hauliers, with yet more rises to come, the AA reveals today.

A new round of fuel protests is due to start in London next week as critics demand that the Chancellor slash duty. Motoring groups fear the £6 gallon is weeks away as industry experts predict oil will top $150 a barrel.

Yesterday the world's biggest oil producer Saudi Arabia was celebrating 75 years of its national oil company but showed no signs of releasing more supplies despite a request from President Bush.

Saudi oil minister Ali al-Naimi stated the 'kingdom's view that the currently produced quantities meet market needs and that the production capacity can meet any additional energy needs.'

City experts said the high oil price was being driven by speculators who, having had a role in the mortgage crisis, have now become active in the oil and gas market.

Some 45 per cent of new car sales are diesels. They have grown in popularity because of their traditionally better fuel economy - until the mid-1990s diesel was cheaper than petrol - and now lower CO2 emissions which mean lower road tax.

But the widening gap as diesel becomes ever more expensive means those benefits are being wiped out.

Since early last week, the price of petrol has risen 1.73p a litre while diesel has gone up 2.66p.

Full article here.