4pm: It is now official.
Jacqui Lait has issued this statement:
"It has been my pleasure and privilege to serve as Beckenham’s Member of Parliament for nearly 12 years now but, with the prospect of a Conservative government after the next election, I have for some months now been considering whether it might be time for me to move over for a younger person. Indeed, I first mentioned that I was thinking about retirement to the Chief Whip in March this year.
Given the probable timing of the next General Election, I thought it only fair to the constituency to come to a final decision over the summer months.
I am therefore writing formally to confirm my intention to retire at the General Election, now expected in 2010. Not only will the new Beckenham constituency be able to move into the exciting years ahead with a younger and refreshing new candidate, but I will be free to take up new challenges while still of an age to contribute fully to the future of our country.
I will obviously remain an active MP until the dissolution of this Parliament and I look forward to working with new candidate for Beckenham over the coming months.
I would like to thank you and all officers and members of the Association for their active support and kindness to me as MP and to Peter and I look forward to being able to thank them more personally in due course."
UNCONFIRMED but ConservativeHome sources say Jacqui Lait MP will become the latest Conservative MP to step down at the next General Election, vacating Beckenham.
After winning the seat for the Conservatives in a difficult by-election at the start of the Blair years, Jacqui Lait will leave her successor a Tory majority of over 14,000.