John Grigg, a historian and biographer of the ex-premier, wants to see a new memorial in honour of the man who, he says, enabled the UK to win World War I.

The statue of Churchill in Parliament Square

There is already a statue of World War II leader Winston Churchill in Parliament Square in London.

Mr Grigg told BBC Radio 4's Today programme: "I think Lloyd George is by far the most eminent statesman of whom there isn't an outdoor statue yet in London.

"There's one in the Palace of Westminster but there's none outdoors. He's one of the great men of history and it's high time there was a statue of him."

But Mr Clark said Lloyd George's political career and war-time reputation are overestimated and he does not deserve another memorial.

Alan Clark says we don't want a new statue

He said: "Lloyd George subsisted for most of his time on balancing acts and coalitions and ended up splitting his own party and going into early retirement. That pleasure we have yet to see from Mr Blair.

"I simply don't see why now all of a sudden we have to have a statue of Lloyd George, unless it's a kind of subliminal push from Mr Blair himself - they seem to have a lot in common."

Lloyd George was a Liberal chancellor in the run-up to World War I and was prime minister from December 1916 until 1922, under a coalition government, dependent on Unionists' support. He eventually resigned when they refused to back him.

His radical policies included a 'People's Budget' in 1909, and as premier he revolutionised the cabinet system. He also introduced longer-lasting, extended unemployment insurance.

War-time mistakes

Mr Clark said the ex-premier ended up in a party of one.

But Mr Grigg said Lloyd George was the first civilian leader to predict the unprecedented scale and horror of World War I. When Britain was challenged by German U-boats, he made the right decisions and appointments and set up the Ministry of Munitions.

But Mr Clark argued that his war leadership was one of his weakest points.

Clement Attlee has a statue in the members' lobby

The MP said he kept on an incompetent commander for internal political reasons when he should have dismissed him.

But he admitted he did make some "groundbreaking" acts - starting the NHS.

Mr Clark added that there should be a statue of Lady Thatcher in the House of Commons' members' lobby, alongside the existing Lloyd George statue, Attlee and Churchill.