Dame Tessa Jowell has announced she will retire as West Norwood's MP after 23 years at the next election.

The announcement has fuelled speculation she is preparing for a bid to run as London's mayor when Boris Johnson's term ends in 2016.

The Labour stalwart, as culture secretary played a central role in bringing the 2012 Olympics to London.

In a letter to her Dulwich and West Norwood constituency party she said retiring was "the hardest decision I have ever taken".

Her announcement drew tributes from Tony Blair and Lord Coe who said she had been an "inseparable part" of the success of the Games.

She added: "It is really too early for anyone to be declaring themselves ahead of the local elections next year and the general election in 2015.

"I love London and, of course, when the time comes will think hard about whether I should offer myself as a candidate."

Former Prime Minister Tony Blair described Dame Tessa as "kind, decent and loyal in a way I have seldom seen in politics".

Mr Blair said: "I always knew I could rely on her and trust her 100 per cent. But I also knew she would never hesitate to tell me what she thought was right and true. That gave and gives her a rare integrity.

"She represents all that is best in Labour and is a great advocate for Britain. I have no doubt that she will continue to do great things in the service of both."

Current Labour leader Ed Miliband said she is a " unique politician" of warmth, spirit, loyalty and generosity.

And Streatham MP Chuka Umunna paid tribute to his " Lambeth neighbour, political mum and Labour legend".