Labour 'failed to connect with Asians in Bradford'
George Galloway's victory in Bradford West was partly due to Labour's failure to connect with the Asian community, the shadow home secretary has said.
Yvette Cooper said her party had not won over young Asians or Muslim women.
Respect Party MP Mr Galloway, expelled by Labour in 2003, held a rally before 2,000 people on Sunday after winning Thursday's by-election by 10,140 votes.
He said he had the support of people of all backgrounds in a "democratic uprising" against established parties.
In taking Bradford West, Mr Galloway overturned a Labour majority of more than 5,000 at the 2010 general election.
He was previously MP for Bethnal Green and Bow in east London.
Ms Cooper told the BBC's Andrew Marr programme the by-election was "deeply disappointing" and the party had "lessons to learn".
"I think it is the case that Labour wasn't connecting enough with young voters in Bradford's Asian community.
"My sense too is that we weren't connecting enough with Muslim women in Bradford."
She said there were clearly "local factors" that had been significant in the constituency and warned against generalising about the Asian community because Labour had been successful in other by-elections with significant Asian populations.
Commentators have suggested Mr Galloway attracted many Asian voters because of his opposition to the war in Iraq and his call for troops to withdraw from Afghanistan immediately.
But the Respect MP has rejected that, pointing out that Labour's candidate was, in fact, a Muslim of Pakistani origin.
He told Sunday's rally in Bradford that his 85% share of the vote in the city's diverse university ward showed he had support of people of all races and religions.
"This is a mass popular rejection of people of all kinds of the existing political class," he said.
Ms Cooper said she was "worried" about what Mr Galloway would do now he had been elected.
"We saw what happened last time, we saw what happened in Bethnal Green," she said.
"We saw how little, in fact, that he did in Parliament and how little he did to stand up for people in east London, so I hope that he will do more this time because he needs to show respect for the people who voted this time."
Labour MP Michael Dugher, former spokesman for Gordon Brown, told the BBC's Sunday Politics that Bradford West was "possibly the first by-election in history that was fought and even won on social media".
"So you had George Galloway with 85,000 followers on his Facebook page [while] our candidate was knocking on doors the old-fashioned way," he said.
The Conservative and Liberal Democrat share of the vote also fell significantly in Bradford West, at the end of a difficult week for the coalition.
Foreign Secretary William Hague, however, said the government should not be "fazed or deterred" by what had been a "controversial" period, including over its handling of the threatened fuel tanker strike.
He told the BBC he believed his colleagues would have been "criticised either way" - whether they had urged people to keep their petrol tanks topped up or not.
Ms Cooper also set out Labour's plans to make law and order a central theme of its campaign in the forthcoming local elections.
"We're going to be campaigning on crime and anti-social behaviour because that is the sort of thing people are very concerned about in streets and communities across the country," she said.