Outside the NHS drop-in centre in Prestwich, north Manchester, it is pouring with rain in near-biblical fashion.

We are in the heartland of Bury South, the constituency held by the Jewish politician Ivan Lewis for the past 22 years, always for Labour. Almost a year ago, on December 20, he resigned from the party, citing antisemitism in Labour as a major concern; although in 2017 he had been suspended from the party over unproved — and unconcluded investigations into — allegations of sexual harassment.

Since 2018, Mr Lewis, who held various ministerial posts in the Blair and Brown governments, has been representing Bury South as an Independent MP and, nursing a majority of just under 6,000 over his last Conservative rival, he decided to run again in that capacity.

But on Wednesday, Mr Lewis dropped a bombshell. He wrote in a Facebook post that it was “the right thing to do” to back Conservative candidate Christian Wakeford in order to “stop Corbyn.

“Many will be voting Conservative for the first time and it will require much soul searching. But it is the right thing to do,” he said.

The statement was particularly surprising given he told the JC last week there was “a definite appetite for me to stand. There was a massive group of Labour-inclined voters who can’t bring themselves to vote for Corbyn, who struggle with the notion of voting Conservative — and they wanted a voice”.

On the issue of Brexit, Mr Lewis might have been thought to have a problem. He was a Remainer, but Bury voted to leave the EU by more than 8,000 votes. However, he said he respected the result of the referendum and believed it was time to support Boris Johnson’s deal as “the right thing to do”.

He said he was receiving good support locally, not least from people who won’t vote Labour. As we stood outside the NHS drop-in centre — which was under threat of closure but was reprieved after Mr Lewis campaigned on its behalf — a man walking a dog rolls up.

“Are you going to vote for me?” asked Mr Lewis. “I won’t vote Labour,” responded the man, unprompted. “I hate Corbyn, he’s thick, he’s a racist, he supports the IRA…anyone but Labour.” Mr Lewis said: “I’m not Labour now, I’m Independent”. “Aye”, says the dog-walker. “And I hate Boris, too”. He said Mr Lewis probably had his vote. Mr Lewis smiled and said he didn’t stage-manage the encounter, and he was clearly right, as other people said much the same thing.

In a kosher cafe and delicatessen in Whitefield, another part of the constituency home to Jewish voters, a man came forward to ask Mr Lewis: “Have you got any chance of winning, or am I wasting my vote if I vote for you?”

At times it was like being in a Jewish episode of Coronation Street as Mr Lewis met and greeted. A gang of women in the kosher cafe readily agreed to have their picture taken with the candidate, whom they clearly knew. “Who’s this for?” they chorused, only for one to roar, when learning the picture is for the JC: “I haven’t got me teeth in!”

It wasn’t just Jewish voters who knew and embraced Mr Lewis as the person who represented them in Parliament for 22 years. He got a good reception at the school gates in a white, working-class part of the constituency, Radcliffe. He is a local boy, born and bred in Prestwich, with a background in social work before he entered politics.

These days he wears a kippah full-time, and acknowledges that he has become more observant in the past couple of years. What response was there from his non-Jewish or Muslim constituents? “Nothing whatsoever”.

His Jewish identity, he said, “has always been central to my political values,” and for him it has been “heartbreaking to have to choose between my Labour and Jewish identity. There was only one way I could go.”

For some voters, the hustings held at Prestwich Hebrew Congregation to a packed crowd was likely to have been an influential occasion. The audience included supporters of Mr Lewis from the local mosque, as well as Momentum-linked members of Bury South’s Labour Party. The chair, the Jewish Leadership Council’s chief executive, Simon Johnson, made it clear from the start that he would not accept disrespectful behaviour.

So a nervous Lucy Burke, the Momentum-backed candidate standing this time for Labour, received a relatively sympathetic hearing, as she undercut potential a ntipathy by declaring upfront that “I understand why many people feel unable to vote Labour”. It was a source of “deepest sorrow”, she said, that relations between Labour and the Jewish community were “at an all-time low”, and said that she would “stand with the Jewish community”.

The Conservative candidate, Christian Wakeford, a councillor on Lancashire County Council, presented himself as a defender of religious freedom; while the Lib Dem hopeful, Richard Kilpatrick, a councillor for Didsbury West, is a former teacher who managed to make his opening remarks without mentioning the Jewish community or antisemitism. Mr Wakeford also suggested that voting for Mr Lewis, rather than Conservative, would split the vote and allow Labour in, a charge Mr Lewis had rejected.

But for a number in the audience, Mr Lewis’s barnstorming performance reminded them of his long career in Parliament and his familiarity with their concerns. “My role as a bridge between the Jewish and wider community has never been more important,” he told them.

It seems unlikely that role can continue following his call for voters to plump for his rival.