Amid the sea of flag- waving pro-Palestinian protesters marching past Parliament last week was an obscure local mayor whose presence will have gone almost unnoticed.

Afterwards, the mayor issued a statement declaring his commitment to the cause. ‘I was heartened to march with 500,000 people in solidarity with the people of Gaza,’ it read. ‘Amid the darkness of the past three weeks, it was an important and powerful display of humanity.

‘People across the world are demonstrating to demand a ceasefire now. World leaders must listen and work together to find a political solution to this crisis. There must be an immediate ceasefire.’

They are words to chill Keir Starmer’s heart. For the individual who issued them is Lutfur Rahman, the Mayor of Tower Hamlets. And, ominously for the Labour leader, they show Rahman is flexing his muscles just as the Opposition tears itself apart over Gaza.

He has form in causing trouble for the party. A former Labour mayor of Tower Hamlets, he was removed as the party’s candidate in 2010 over allegations of links to a fundamentalist group and voting irregularities. Rahman then inflicted a humiliating defeat on the Labour machine last year when he ousted its elected mayor in Tower Hamlets.

Ominously for the Labour leader, Lutfur Rahman (pictured, centre) is flexing his muscles just as the Opposition tears itself apart over Gaza

Labour’s position over Gaza marks Starmer’s gravest crisis since his tenure began. He has been forced to walk a political tightrope between showing his support for Israel against Hamas terrorists and responding to growing calls from party members for a ceasefire — something he opposes

The 58-year-old’s controversial Aspire Party swept to power to take control of the council for the first time.

All 24 Aspire councillors are Bangladeshi Muslims, and their victory makes the East London borough the first Muslim political stronghold in Britain.

But Tower Hamlets is far from the limit of Rahman’s ambitions. He is said to be considering fielding Aspire candidates to challenge Labour incumbents at the next election. Specifically, there is talk that Aspire is targeting 30 parliamentary constituencies where Muslim voters hold the balance of power.

Should Rahman carry out the threat, it could potentially derail Starmer’s dream of being the first Labour leader to win a general election since Tony Blair in 2005 as Muslim voters reject the leadership’s stance on the Middle East.

Labour’s position over Gaza marks Starmer’s gravest crisis since his tenure began. He has been forced to walk a political tightrope between showing his support for Israel against Hamas terrorists and responding to growing calls from party members for a ceasefire — something he opposes.

Sixteen frontbenchers have joined the rebellion, and the growing public row has caused alarm at the highest levels of the party.

Just yesterday, the Labour leaders of Burnley and Pendle councils in Lancashire called upon Starmer to resign over his failure to back a ceasefire, with Burnley leader Afrasiab Anwar claiming Starmer had ‘not stood up for Labour values’.

Starmer, with a 20-point lead in the opinion polls, thought he was cruising to victory.

A former Labour mayor of Tower Hamlets, Rahman was removed as the party’s candidate in 2010 over allegations of links to a fundamentalist group and voting irregularities. Pictured: At a rally in 2014 alongside ex-mayor of London Ken Livingstone and former MP George Galloway

Sixteen frontbenchers have joined the rebellion against Starmer, and the growing public row has caused alarm at the highest levels of the party. Pictured: Demonstrators hold banners on October 31

But he is now struggling to contain bitter divisions as more than 60 MPs have gone public with their demands for a ceasefire. In addition to those 16 frontbenchers, some of the party’s most senior politicians, including Scottish Labour leader Anas Sarwar, London Mayor Sadiq Khan and Greater Manchester Mayor Andy Burnham, have joined in.

The revolt has also spread deep into Labour’s local government base with more than 350 Muslim Labour councillors signing an open letter calling for an immediate ceasefire. There have been scores of resignations from the party.

This all explains why, in a speech on Monday, the Labour leader tried to restore calm, saying that he understood concerns at the loss of life in Gaza but argued a ceasefire would only ‘embolden Hamas’ and that the only credible approach was to back temporary ‘humanitarian pauses’ in the fighting.

But the leader cannot avoid the fact many of his MPs, with large numbers of Muslim voters in their constituencies, fear for their electoral prospects.

The constituencies of eight frontbenchers who rebelled are all among the 20 with the highest number of Muslim voters, according to the 2021 census. They include the seat of Rachel Hopkins, the shadow veterans minister, whose 8,700 majority in Luton South, where the Muslim vote is 30 per cent, could be threatened.

It is a similar story for Yasmin Qureshi, the shadow equalities minister, who infuriated Starmer when, at Prime Minister’s Questions last week, she criticised ‘the collective punishment of the Palestinian people in Gaza’.

Her behaviour was a direct challenge to Starmer’s authority — he was sitting just a few feet from her in the Chamber. Qureshi is defending a 7,600 majority in Bolton South, where Muslims constitute 31 per cent of the vote, the 17th-highest proportion of any constituency in the country. The story is the same in many other places. For instance, Labour whip Kim Leadbeater has one of the smallest majorities in the Commons, only 323 in Batley and Spen, where Muslim voters account for 20 per cent of the electorate.

The prospect of Rahman fielding his own candidates will only harden their views. Not that any of the rebels have much love for the firebrand mayor.

The 58-year-old’s controversial Aspire Party swept to power last year to take control of the council for the first time

Rahman was Labour leader of Tower Hamlets council from 2008 to 2010 before running independently for the mayoralty in 2010, then winning re-election in 2014 with new party, Tower Hamlets First.

But in 2015, he was removed from office after being found guilty by a civil election court of securing votes by deploying ‘corrupt and illegal practices’. After a ban, however, he was back in 2018 with his new party Aspire, and secured last year’s thumping victories.

One senior Labour MP told me: ‘The thought of independent Muslim candidates terrifies some of my colleagues. Keir should be tougher with frontbenchers who are speaking out. Discipline is essential if we are to win the next general election. We have to get a grip.’

Yet other than former shadow minister Andy McDonald, who was suspended from the party after making a ‘deeply offensive’ speech at a pro-Palestinian rally, Starmer has failed to discipline any of the rebels. And it’s unlikely they would listen anyway.

Naz Shah, a shadow minister who has joined the rebels, has a majority of 27,000 in her constituency of Bradford West, which has a Muslim population of 57 per cent.

But she will be only too aware that George Galloway, the former Labour MP who founded the Respect Party to oppose Labour after the 2003 Iraq war, won in the constituency on a 36 per cent swing from Labour in a 2012 by-election.

The party is still trying to clear up the mess caused by Starmer in a radio interview. Asked if ‘cutting off power, cutting off water’ was a legitimate course of action by Israel, he replied: ‘I think Israel does have that right.’

It took him 12 days to ‘clarify’ his position — but for many, the damage was done. As one Labour MP said: ‘We are always reactive rather than pro-active and we are too slow when we are reacting.’

The leader cannot avoid the fact many of his MPs, with large numbers of Muslim voters in their constituencies, fear for their electoral prospects

Voters have noticed Starmer’s struggle. The latest research from Deltapoll found Starmer’s personal rating down by 12 points from +7 to -5.

The Muslim Census group recently surveyed 30,000 British Muslims and suggested only 4.8 per cent would vote Labour now, against 71 per cent at the last election.

As the study was done on social media, mainstream polling companies have derided it as meaningless but spreadsheets are doing the rounds within Muslim communities detailing the positions on Gaza taken by individual Labour MPs.

In Scotland, where 75 per cent of Muslims live in three Glasgow constituencies, there is talk of putting up independents who would split Labour’s vote, wiping out anticipated gains north of the border.

This weekend, yet again, Rahman will be joining tens of thousands marching against Israel’s operations in Gaza.

Starmer and his supporters will be desperately hoping that he and other opponents of the conflict don’t get even more vocal and angry with time — or Labour will pay a heavy price at the polls.