Lord Mandelson used a JC event this week to launch a stinging attack on Jeremy Corbyn — and reveal the extent of his own Jewish roots.

Speaking at the JC Editor’s Choice evening at the JW3 community centre on Monday night, the Labour peer, described growing up in Hampstead Garden Suburb, in north-west London, and his father Tony’s tenure as advertising director of the  JC.

As the youngest son of Mary Morrison, the daughter of Labour firebrand Herbert Morrison, Lord Mandelson acknowledged he was not brought up in a particularly Jewish household.

He said his father was “an atheist” who came speedily to Israel’s defence at times of conflict such as the Six-Day War. 

Recalling his father’s time at the JC, Lord Mandelson said the newspaper where he worked from 1947 until retirement  was “his life.” 

The peer told the audience that his own main connection to Judaism these days was the occasional Friday-night dinner. He said: “I think of myself being Jewish when I’m with Jewish families on a Friday night.

“If I’m in London on Friday night there are some people I like to go to and have a Jewish happy Friday night with. That basically is my link.”

Answering questions put by JC editor Stephen Pollard, the peer said he was working “every single day” to help rescue the party from Mr Corbyn’s leadership.

Lord Mandelson, a former European Commissioner and a Cabinet minister in Tony Blair’s government, revealed that, “I work every single day, in some small way, to try to move forward the end of his tenure in office.

“I work every day — an email, a phone call, a meeting with Labour MPs.

“I try and galvanise them. Every day I do something to rescue the Labour Party from his leadership.”

Asked whether the party could recover from its current low standing, Lord Mandelson said: “Look, the Labour Party at the moment is on life support. I think it’s not dead, I think it can recover and pass out of the A&E route in due course, if we want to get another leader.

“The problem with Jeremy is — it’s not as if he’s a maniac, it’s not as if he’s a nasty person. It’s that he literally has no idea in the 21st century how to conduct himself as a leader of a party putting itself forward in a democratic election to become the government of our country. It’s as if he’s in a parallel universe.”

He added that, in his view, Mr Corbyn “will gravitate to whatever revolt, insurrection or protest movement that’s in sight. Perhaps he could be a little more discriminating. 

“That’s his whole politics — he’s been like it for 35 years. He was not a frequent supporter of the last Labour government — he voted against it 500 times.”

Asked why he hadn’t abandoned Labour altogether, Lord Mandelson  said that, having grown up in a staunch Labour household, he would resent “handing over the title deeds to Jeremy Corbyn.”

Lord Mandelson spoke of his admiration for Mr Blair’s pro-Remain speech ahead of this week’s Brexit Bill debate in the House of Lords.

He said: “A speech of that quality could not have been delivered by another person — to think it through, to write it.

“I do have plenty of people I know, friends, who rather parted company with Tony mainly over [the] Iraq [war] and other things.

“I’ve had a lot of emails and texts over the weekend saying ‘all credit to him for showing the courage to speak out’.”