A Conservative MP who broke lobbying rules in a WhatsApp exchange exposed by The Telegraph’s Lockdown Files investigation has said he will stand down at the next election.

Steve Brine, who has represented Winchester and Chandler’s Ford since 2010, said it was time for him to reflect on a “new chapter” in his life.

Mr Brine, the chairman of the Commons Health and Social Care Select Committee, said in a letter to his local Tory association that he had always intended to “serve twenty years or four general elections”.

“This was not a hard and fast rule and I don’t think anyone could have predicted the events of the past 13 years, but it feels like the right time now, both for myself and for the family,” he said.

“Going forward, I feel I can pursue some of the things I care about – in health and perhaps elsewhere – both outside Parliament and within Parliament.”

In March, a leaked WhatsApp message published as part of the Lockdown Files showed Mr Brine contacting ministers and officials on behalf of Remedium, who paid him £1,600 a month.

Following an investigation, the watchdog concluded that Steve Brine had twice failed to make it clear that he was a paid consultant to Remedium Partners when he contacted ministers on behalf of the health care recruitment agency.

However, critics said Mr Brine “came off lightly” as he will take no further action than to “rectify” his breach with an apology and a promise not to do it again.

Winchester and Chandler’s Ford will be one of the main targets for the Liberal Democrats in the next general election, widely expected next year.

At the 2019 general election, Mr Brine’s majority was 985, down from 9,999 two years earlier.

A Liberal Democrat source noted that he was the latest in a string of Conservative MPs in ultra-marginal seats who have announced they will stand down before the next vote.