Jeremy Corbyn’s initial slowness to act against anti-Semitism allowed it to “fester” in the party and Labour would not be rowing about it now if he had taken action more quickly, a highly respected peer has said.

Lord Dubs, who escaped the Nazis on a Kindertransport from Prague in the summer of 1939 when he was just six years old, said the Labour leader is now “doing okay” at tacklinganti-Semitism.

But as a new row over the problem threatened to overshadow the party’s conference in Brighton, the Labour peer warned “you’ve got to nip these things in the bud immediately”, noting “the Holocaust began with words”.

Lord Dubs said Labour is not anti-Semitic and blamed “discordant” voices, who made comments allegedly targeting Jews at a fringe event on Monday and on the conference floor on Tuesday, for the controversy.

But speaking to reporters after a Jewish Labour Movement fringe event on refugees, whose rights he has championed, the peer said: “I think initially the party moved less quickly than it should have done to deal with anti-Semitism, it just moved slowly and I think it’s sort of festered a little bit and I think it’s been dealt with.

“But I think it was a slow move, I think if the party had moved instantly then we wouldn’t be talking about it, I think the party moved a bit more slowly and then you’ve got Shami Chakrabarti doing the report and things began to take a turn for the better.

“But I think there was just a pause at the beginning when it didn’t happen and I think somebody has said, a lot of people have said, that the Holocaust didn’t begin in the gas chambers, it ended with the gas chambers, it began with words.

“That’s what we’ve got to bear in mind.

“You’ve got to nip these things in the bud immediately, I’m not saying there are going to be gas chambers in Britain but things get worse if you don’t deal with them immediately, and the Holocaust began with words.”

He also said Mr Corbyn was now dealing with he issue.

“I think initially when the issue arose about a year or two years ago, I think the party could and should have moved faster because you’ve got to nip these things in the bud, I think he’s doing okay since then,” he said.

“I think he’s well aware of the difficulty we’d be in if there was a hint of anti-Semitism about us and I think he will regret as much as anybody things that were said in the conference.”