CONSERVATIVE MP Louise Mensch is to quit politics and move to New York to be with her rock band manager husband and their family.

The backbencher, who shot to prominence as a member of the Culture, Media and Sport Select Committee which investigated the phone-hacking scandal, said she was devastated but it was a "necessary decision".

The move will trigger a by-election for her marginal seat in Corby, Northamptonshire.

Mrs Mensch carved out a high-profile for herself and had been tipped for a major post.

But she had been forced to divide her time between the UK and the US.

Her husband, Peter Mensch, is manager of rock band Metallica.

Mrs Mensch told the Prime Minister in a letter: "I have been struggling for some time to find the best outcome for my family life, and have decided, in order to keep us together, to move to New York.

"It is only through your personal intervention, delivered quietly and without fanfare, that I have been able to manage my duties for this long."

Mrs Mensch told Mr Cameron that letting her work from her constituency on Thursdays and Fridays allowed her to spend more time with her children.

However, she added: "It has not proved to be enough. I am very sorry that, despite my best efforts, I have been unable to make the balancing act work for our family."

The Prime Minister said he was aware it had been "a particularly difficult period for you and your family".

He added: "It is with enormous regret I accept your resignation as the Member of Parliament for Corby and East Northamptonshire, a seat that had been Labour for 13 years before you. I do so only because I wish to support you in acting in the best interests of your family, which must come first."

Mr Cameron hinted she had been in line for a role in the Government.

He said: "It goes without saying that I had wished to see you serve for longer and at a more senior level."