Areas with significant Muslim populations saw a dip in support for Labour, with four independent candidates elected to parliament running on a pro-Gaza ticket.
Zarah Sultana, a Labour MP who was re-elected, told the BBC that the party had "clearly lost support in parts of the country because of its position on Gaza".
"The party has to seriously recognise and acknowledge the issue," she added.
New Prime Minister Keir Starmer's party has faced criticism since the start of the Israel-Hamas war on October 7 for its delay in calling for a ceasefire.
Since February, the party has called for an immediate ceasefire and committed to recognising a Palestinian state, but without giving a definite timeline.
Alongside the four independent running on a Gaza ticket, another pro-Palestinian MP elected was Jeremy Corbyn.
The former Labour leader won as an independent candidate after being barred from standing for Labour for his handling of claims of anti-Semitism within the party.
Labour did however succeed in winning back a seat from left-wing veteran George Galloway who ran a pro-Palestinian campaign in the seat he won from Labour in a by-election earlier this year.
'Abandoned'
Around four in five UK Muslims voted Labour in 2019, reinforcing the historic links that were forged after the mass migration of workers from Pakistan in the 1950s and 1960s.
However, in seats where Muslims make up over a quarter of the population, the Labour vote has decreased by 23 percent this time, according to LBC radio.
A campaign called "The Muslim Vote" backed dozens of independent and other candidates it deemed as supporting Muslim interests. On its website, the group says the election "signals a shift for Muslims -- no more political apathy".
One prominent Labour figure conceded defeat to an independent candidate after losing a majority of more than 22,000.
Jonathan Ashworth, who was set to become a minister under Starmer, lost his seat to Shockat Adam, who declared, "This is for Gaza" after his win, waving a keffiyeh, the symbolic Palestinian scarf.
Ashworth had held the Leicester South seat, which has a 30 percent Muslim population, for over a decade, and it had been a Labour safe seat since 2005.
In several other seats considered safe for Labour, the party's candidates narrowly clung on with independent candidates depleting their votes.
Vaz Shabir, an unsuccessful independent candidate in Keighley and Ilkley in northwest England still considered the night's results a triumph.
"The Muslim vote felt powerless until last night", Shabir told AFP. "We showed Keir Starmer: ignore us at your own peril."
"It is definitely clear that many Muslim voters abandoned Labour this election," said Maria Sobolewska, a political science professor at University of Manchester.
"There is no doubt that this is because they do not trust Labour on Palestine," she added.
However, pointing to a similar loss of support among Muslim voters following the Iraq War in 2003 under a Labour government, she pointed out that while the vote was a strong protest, such defections may not last long.
"It does not in my view represent a major electoral realignment of Muslim voters."
'Never again'
Some turned to the Green party as an alternative because of its support for a ceasefire since early in the war.
Amie Kirby, a 24-year-old from Salford in northern England, had always voted Labour in the past, but backed the Greens this election, saying its candidate's "strong stance on Gaza was definitely an influencing factor".
Aghileh Djafari-Marbini is a charity worker from northwest London who previously voted Labour. This time, she campaigned for a local independent candidate who was expelled from the Labour party as part of Starmer's purge of Corbyn allies.
"Grassroots Muslims are really, really angry," Djafari-Marbini told AFP.
She cites interacting with a number of Muslims declaring, "never again", saying "we were fooled after the Iraq War".
However, while she admits victory for the four independents was "a historic moment", Djafari-Marbini added that she needed to "be realistic about what that can achieve".
"If I was a Labour Party strategist now... having done all the celebrations, I would be scared of this landscape that developing," she added.
