Michael Howard has said he would "entirely understand" if the rising price of petrol prompts further protests across the country.

The Conservative leader was speaking as a combination of continuing turmoil in the Middle East and strong demand in the US and China pushed oil prices to new highs.

But the Liberal Democrats have slammed the comments, branding them "irresponsible".

Although oil prices eased slightly on Wednesday, they have risen by around 25 per cent so far this year.

And as concern grows about the cost of petrol prices on British forecourts, Howard renewed his call for ministers to take action.

The government is planning to increase fuel duty by 1.92 pence per litre from September 1.

But Howard said the chancellor should now scrap this move.

Protestors involved in the fuel protests which took place four years ago have warned that they could renew their calls for moves to ease the cost of petrol

And the Tory leader said that as long as protests were peaceful, his party could offer its support.

Asked on BBC Radio 4 if the Conservatives would back new protests, he said: "I think that as long as they are peaceful and within the law they may well be supported."

"I can understand that people might be very angry indeed if the government were to proceed with an increase in fuel duty at this time - it would cause great hardship to many people," Howard added.

"I would entirely understand if they wanted to protest peacefully and within the law."

But the Liberal Democrats branded support for the protestors as "the height of irresponsibility".

"During the last fuel protests millions of people had their lives disrupted and thousands of businesses lost millions," said Liberal Democrat ODPM spokesman Edward Davey.

"For a former home secretary to incite such disruption is astounding. Mr Howard's naked opportunism just days before an election will backfire.

"People have a legitimate right to protest, but responsible politicians should not encourage action that has been shown to bring the country to a standstill in the past.  Mr Howard's judgement is in severe doubt."

Davey said that the war in Iraq had been partly responsible for pushing up oil prices, adding that the Conservatives had given their backing to the war.