A former star of hit TV show Law and Order has pulled out of the race for the Republican candidate for President of the United States after a string of poor showing in the primaries.

Fred Thompson announced his decision earlier today and it is not known if he will back any of his opponents for the nomination. In 2004 he backed Senator John McCain.

“I have withdrawn my candidacy. I hope that my country and my party have benefited from our having made this effort,” he said.

A moderate opponent of gay rights, during his short campaign Mr Thompson said he is not in favour of a constitutional amendment to ban gay marriage, proposed by President Bush, but would act to ensure the issue remains at state level.

Thompson, 65, is a former Senator from Tennessee and starred opposite Harrison Ford in The Hunt for Red October.

He has appeared in over 20 Hollywood movies since 1985.

He has combined entertainment work with law and politics throughout his adult life and his Southern drawl and bulky frame made him a credible candidate for what Americans imagine the leader of the free world should look like.

He became a lawyer in 1967 and was co-chief counsel to the Senate Watergate Committee in its investigation of the Watergate scandal from 1973 to 1974.

Mr Thompson represented Tennessee in the Senate from 1994 to 2003.

As well as his recent work on TV police drama Law and Order, he is a well-know radio host in the US.

Meanwhile the Democratic race turned nasty in a CNN debate last night, with Hillary Clinton and her Senate colleague Barack Obama trading verbal blows and both accusing the other of not telling the truth.