Chris Williamson faces being deselected as a Labour MP by local activists should the party allow him back into the fold, following anger at his comments about antisemitism.

The Observer understands that plans are already in place to remove him as Labour’s candidate for Derby North, even if the party opts to reinstate his membership following his suspension.

Under party rules, local Labour and trade union branches have the chance to demand a different candidate. The process has already begun before a possible election this autumn, with all Labour MPs asked to make clear whether they intend to run again.

There is frustration among both local party members and trade unions over Williamson’s candidacy. Some suggested that he could have been deselected before the last election had there been the time and opportunity to do so.

“We are prepared to take on that responsibility if necessary,” said a local source. “It’s frustrating, because he should be dealt with through the party’s central processes.” Another said: “There is a very strong feeling locally about what has happened. There is already a lot of talk about [deselection] and it is 90% there.”

The MP was suspended again on Friday only two days after being reinstated, following a backlash from Labour MPs, peers and staff members. More than 60 Labour MPs had signed a motion calling for his suspension to be reimposed. Keir Starmer, the shadow Brexit secretary, and Tom Watson, the deputy leader, were among those to raise public concerns.

Williamson had been reinstated after a party panel concluded that he should receive only a reprimand for suggesting the party was “too apologetic” about antisemitism. The Equality and Human Rights Commission is investigating Labour over antisemitism. That investigation was launched after revelations, first published by the Observer, that senior party figures demanded lower punishments for some members accused of antisemitism.

All Labour MPs have to undergo a reselection process to run at the next election, under a so-called “trigger ballot” system. The party recently made it easier to use the system to remove the incumbent MP.

The new rules state that either a third of local party branches or a third of local trade union branches can demand a new selection process. The incumbent MP is then included on a shortlist of new candidates for the seat. It is understood that three out of seven local party branches are already prepared to oust Williamson. Several trade union branches are in a similar position.

Williamson tweeted on Friday night: “They say a week is a long time in politics: it seems two days is even longer. I’m naturally concerned by the lack of due process and consistency in how my case is being handled. I’ve been a loyal Labour member for 43 years, and will do my utmost to fight for my membership.”