Muslim voters across the UK are feeling unprecedented discontent with the Labour party, campaigners said after the Batley and Spen vote, as George Galloway promised his party would fight possible future byelections in London and Leicester. “There is pretty unprecedented dissatisfaction among Muslim voters, not just in Batley, but around the country,” said Ali Milani of the Labour Muslim Network. He said that while Labour clearly did not lose the Muslim vote completely in Batley and Spen, the loss of a sizeable number of votes should cause concern among the leadership. “Batley and Spen should be won by Labour easily,” Milani said. “There are seats in places like London, Bradford and Sheffield with significant Muslim populations which are going to make Batley and Spen look like a picnic if we lose any more ground on this. This is the moment, the alarm bells have gone off, we need to act now.” On Monday, Galloway, the divisive candidate and pro-Palestine campaigner who won more than 8,000 votes in the West Yorkshire constituency, suggested he would stand in Leicester East should there be a byelection there after the trial of Claudia Webbe, the Labour MP turned independent who is facing a harassment charge. Meanwhile Apsana Begum, the Labour MP for Poplar and Limehouse in east London, faces trial in July on housing fraud charges, which could trigger a byelection if she is found guilty. Census data indicates it had a Muslim population of 33.6% in 2011. Leicester East has a large Hindu population, alongside those of Muslim and Sikh faiths. Galloway suggested a controversial Labour campaign leaflet distributed to Muslim voters in Batley and Spen, which criticised the Conservatives and featured a picture of Boris Johnson alongside the Indian prime minister, Narendra Modi, would hurt the party there. While there are concerns in Labour about Galloway gathering momentum at future elections, some dismissed his potential to have any significant impact. One Labour MP who campaigned in Batley and Spen said they were ready to face up to future challenges from Galloway and his allies. “You will always get chancers … and people who want to spread division. And if we want Labour to be a party that represents a broad church of voters we have to be ready to take them on,” they said. But regardless of Galloway’s targets, sources within Labour urged the Labour leader, Keir Starmer, to take action amid growing Muslim discontent with the party. Milani said a briefing attributed to Labour sources, one of which suggested the party “lost the conservative Muslim vote over gay rights and Palestine”, was a “slap in the face” to Muslim party members. “It is deeply upsetting for briefings and for the commentary to be so deeply rooted in Islamophobia,” he said. Mustafa Al-Dabbagh, a spokesperson for the Muslim Association of Britain, said: “We’re speaking to British Muslims on a daily basis and they feel alienated. Muslims feel like they are not being taken seriously by the leadership on the Labour party. There seems to be an attitude that Muslims have always voted Labour, so they’re always going to.” He said the party needed to take a stronger stance on tackling Islamophobia as well as on foreign policy issues. “The Conservatives have left Labour with an open goal to come and engage with Muslim constituents and it’s not doing so. You have a government that ignores foreign policy issues like Palestine and Kashmir, and you have an opposition that equivocates,” he added. “When you’ve got Labour party officials briefing frankly Islamophobic statements and making Muslims feel like they’re not part of the wider electorate then I’m sorry, what do you expect from us?” he said. However, the MP for Birmingham Perry Barr, Khalid Mahmood, said Labour was doing as much as it possibly could for Muslim voters and insisted “there’s absolutely no issues around that”. He said: “Saying the Labour party is not in tune with Muslim voters – I think there’s been a hype created against the Labour party deliberately by the Conservatives, and also by the George Galloway campaign, but that isn’t the truth.” The MP Shabana Mahmood, Labour’s national campaign coordinator, told Sky News the party did secure the support of the Muslim community in Batley and Spen but had some “significant issues”. She said: “George Galloway was able to go in and spread a politics of fear amongst people. We also had a lot of propaganda spreading about Labour’s position on some issues across WhatsApp and other social media platforms and we had to challenge that.”