Karl Rove, President George W. Bush’s long-standing political adviser, has announced he is to resign at the end of this month.

The decision to step down comes as poll ratings for Mr Bush remain at the lowest level since his election in 2000.

Mr Rove, a long time political ally of the president, was the architect of Mr Bush’s controversial victory in 2000 and his re-election three years ago.

But in an interview with The Wall Street Journal, Mr Rove said he was resigning to return to his home state of Texas and spend more time with his family.

Mr Rove said he first floated the idea of leaving the White House a year ago but delayed his departure because of the Democrats victory in Congressional elections at the end of last year.

He also said developments in Iraq, where more than 3,600 US soldiers have lost their lives, and growing unease about the level of immigration in the US delayed his decision to go.

But in Monday’s interview he said: ”There’s always something that can keep you here, and as much as I’d like to be here, I’ve got to do this for the sake of my family.”

Mr Rove played a key role in one of the biggest controversies to hit the Bush presidency after the identity Valerie Plame, a CIA operative, was leaked to the press. Ms Plame implicated Mr Rove as a factor in the leak and White House involvement.

Although critics called for Mr Rove’s resignation over the case, the White House and Dick Cheney, the vice president, backed his decision to stay.

In the interview in which he indicated his desire to step down after 7 years in Washington, Mr Rove predicted that Hillary Clinton would win the Democratic presidential nomination and called her ”a tough, tenacious, fatally flawed candidate”.

Mr Rove has been a political adviser to Mr Bush for more than a decade. He worked with him closely before he became governor of Texas in 1993.

Before joining the White House, Mr Rove was president of Karl Rove & Company, the Austin, Texas-based public affairs firm he founded.