From the start of the election campaign it was a chain around the neck of Gordon Brown, whose pledges on British workers and balanced migration were continually called into question.
Equally, Nick Clegg, while riding a wave of popularity, received the most critical attacks for his planned amnesty for illegal immigrants and his regional migration policy.
Faring better than his rivals, David Cameron still did not escape unscathed and was constantly pressed, in vain, to put a figure on his proposed annual cap on the number of foreigners coming to Britain.
The BNP, meanwhile, seized on widespread public concerns about immigration to mount their strongest bid yet to gain a seat in the House of Commons. In a sign of its significance, immigration was the only issue to have a specific question in all three of the leaders’ debates.
Just two days into the formal campaign official figures suggested that about 98 per cent of new jobs created under Labour had been filled by immigrants, delivering an early hammer blow to Mr Brown.
But it was in his encounter with Rochdale pensioner Gillian Duffy that immigration proved the source of the Labour leader’s most damaging gaffe of all. It was Mrs Duffy’s question on immigration that he blamed for “annoying” him when, in his car, with his microphone still on, he describing the Labour voter as a “bigoted woman”.
Clegg’s promise to allow illegal immigrants who had been in Britain for 10 years to remain here proved to be the largest stick with which his opponents beat him.
One analysis suggested it would result in more than a million people being granted British citizenship.
The Lib Dem plans to use the points-based system to make it easier for migrants to go to regions where they were most needed sparked ridicule.
Cameron’s Tories promised to impose a limit on immigration but, despite regular grilling on what that level would be, the party leader would only say net migration — the difference between those arriving and those leaving — would be tens of thousands not hundreds of thousands.
Opponents dismissed the move as “complete nonsense” because a cap cannot stop EU citizens from coming to Britain to live and work. Telegraph.co.uk