Ken Livingstone has been suspended from holding office in the Labour Party for one year after being found to have “brought the party into disrepute” over a series of incendiary comments relating to Adolf Hitler supporting Zionism.

However, the former London mayor will be re-instated as a member of the party, having initially been suspended pending a hearing. He will be free to vote in Labour elections and attend some party meetings.

Following an 11-month suspension, Labour’s disciplinary panel – the National Constitutional Committee – reached its decision to ban Mr Livingstone for an extra year from standing for election office within Labour and attending constituency party meetings. The ruling followed a three-day hearing into his remarks.

The party found that he had breached Labour’s rules, adding: “The NCC consequently determined that the sanction for the breach of Labour Party rules will be suspension from holding office and representation within the Labour Party for two years.

“Taking account of the period of administrative suspension already served the period of suspension will end on 27 April 2018.”

Mr Livingstone said after the hearing: “Today’s Labour Party panel extended my suspension for another year because of my political views, not because I have done anything to harm the Labour Party.

“The Labour Party’s disciplinary process was not in accord with natural justice in a number of ways. For example the panel hearing was not held in public, despite the fact that it could have been under Labour’s rules. I was suspended for more than 11 months before the hearing was held.

“Scheduling the final day of this disciplinary hearing, on the day the Labour Party launched its campaign for the 4 May elections, was a supreme misjudgment by whoever planned this in the Labour Party headquarters.

“It was clearly not in Labour’s interests as the hearing will inevitably generate unfavourable headlines at a time when Labour should be focused on campaigning.

“I will be launching a campaign to overturn my suspension of party membership.”

Ken Livingstone on Hitler and MP Keith Vaz

It was widely expected that Mr Livingstone would be expelled from the party and some Labour MPs will likely see his punishment as lenient.

Mr Livingstone, a supporter and old friend of Jeremy Corbyn, the Labour leader, has been a member of the party since 1969 but was previously exiled for four years after his decision to stand as an independent candidate for London mayor in 2000. He returned to the party four years later.

His latest suspension follows remarks he made in April last year during a radio interview that the Nazi leader had supported Zionism in the 1930s before he “went mad and ended up killing six million Jews”.

Commenting on the decision to suspend but not expel Mr Livingstone, Simon Johnson, chief executive of the Jewish Leadership Council, said he was “deeply disappointed at the decision”.

“A temporary suspension is no more than a slap on the wrist,” he said. “Mr Livingstone’s inaccurate and antagonistic comments including over the past 40 years have had a huge impact on the Jewish community.

“We feel that the Labour Party should have had the courage to address this deeply offensive behaviour with a firmer penalty.”

The 71-year-old, who was represented by the human rights lawyer Michael Mansfield, had previously conceded he expected to be expelled from the party. In a recent interview with The Independent, however, Mr Livingstone remained defiant, insisting he would challenge the decision via a judicial review.

Comparing the secretive practices of the NCC to the North Korean regime, Mr Livingstone added that the party’s compliance unit likely suspended him because he was supporting Mr Corbyn, rather than being anti-Semitic.

“It was because I was defending Jeremy, which they consider a worse crime,” he added.