Former Sutton and Cheam Liberal Democrat MP Paul Burstow has announced he will not stand in the next general election.

In a Facebook post containing his resignation letter, he said the party "needed to recruit a new candidate to mobilise the membership" and contest the election in 2020.

Mr Burstow, who was first elected in 1997 when he defeated sitting Conservative MP Lady Olga Maitland, served as a junior health minister in the coalition, but was defeated by Conservative Paul Scully in May after holding the seat for 18 years.

He told the Sutton Guardian: "I loved every moment of the job, it was a great honour.

“Like anyone who finds themselves being made redundant the task is picking yourself up and finding a new purpose and that is what I have done.

“I am really pleased to have the opportunities that I now have."

Your Local Guardian:

Conservative Paul Scully, 20,732 votes, defeated Burstow, 16,811 votes, in May's election as part of the wipe-out of Liberal Democrats nationally

"I have been appointed as a part-time professor at City University London where I am working on a mixture of research and teaching around the impact of public policy and government on health and social care.

"It is very much bringing my real world experience of being a minister into that academic setting.

"I have also just been offered a competitive process to become the chairman of the Tavistock and Portman NHS trust, which is an internationally renowned organisation that delivers community based psycho-therapeutic and psycho-analytical approaches to helping people with complex mental health problems."

He added: "The local party needs to be selecting a new candidate to work with colleagues on the council to do the necessary legwork over the next few years to mount a successful challenge to the current conservative MP.

"I think that requires someone who has the energy and drive and youth that I brought to it when I first ran for office in 1992.

"Had I been successful in May I would have worked hard for the constituency over the coming five years but would have been looking to retire voluntarily at the end of the Parliament and look to contribute to the things I care about most beyond Parliament, which are improving mental health and making sure we have great social care."

May 8: Conservative Paul Scully elected to Sutton and Cheam after defeating Lib Dem Paul Burstow

Mr Scully tweeted his thoughts about the resignation:

Elsewhere across London defeated Lib Dem Vince Cable in Twickenham said he would not stand again, and Ed Davey said he might stand again in Kingston and Surbiton, but not against Tory Zac Goldsmith.

Recent highs and the lows]

May 2010: Paul Burstow dramatically holds Sutton and Cheam​

May 2010: Sutton and Cheam MP appointed minister of state for health

September 2010: Sutton MP Paul Burstow's ratings plummet since election

December 2010: Sutton Lib Dem MPs make their decision on tuition fees vote

December 2010: 'Cameron not to be trusted', says Sutton and Cheam MP Paul Burstow in Daily Telegraph sting

Sep 2012: Paul Burstow becomes a member of the Privy Council

June 2013: Sutton and Cheam MP Paul Burstow admits 'lapse of judgement' in Liberal Democrat Lord Rennard sex scandal

November 2013: Surrey Downs withdrawal is "final nail in BSBV coffin"

March 2014: Sutton MP Paul Burstow defends hospital shut-down clause vote

Mr Burstow's letter: "I had already decided some time ago that had I been re-elected in 2015 this would have been my last parliament and I would have been seeking new ways to contribute in the areas I care most about outside of Parliament.

"Over the past five months I have worked hard to set in place the beginnings of a number of roles in health and social care that I have always cared so much about. At the start of October I joined City University as a part time Professor of Health and Social Care. From 1st November I started as Chair of the Tavistock and Portman NHS Foundation Trust in north London.

"I count myself very fortunate that before and since my selection in 1989 I have always enjoyed the friendship and support of so many local members. I said at the Count in May that it has been an honour and privilege to have served as the Member of Parliament for Sutton and Cheam for 18 years. But now it is time for a new candidate."

In a reply John Drage, the chairman of Sutton Liberal Democrats, said: "Paul has been one of the hardest-working MPs in Parliament and that was recognised in an independent Evening Standard study during his term.

"As a Health Minister in the coalition government he was able to set in motion major improvements in the care of older people and mental health. It is great news that his knowledge and expertise in these areas will be harnessed by the new leadership roles he is taking up."