1Voters go to the polls in Crewe and Nantwich on Thursday in a closely watched by-election that could bring further misery for Gordon Brown.
Surveys suggest the resurgent Conservatives are poised to pull off a political coup by gaining their first seat in a by-election for 26 years.
Polling stations close at 10 p.m. in the Labour-held Cheshire constituency with the result expected in the early hours of Friday morning.
The constituency combines the affluent and picturesque market town of Nantwich and its grimmer, more working class neighbour Crewe, once dominated by the railway industry and still a major rail junction.
Losing the seat, held for 34 years by no-nonsense Labour traditionalist Gwyneth Dunwoody, would have little effect on Brown's 67-MP majority in the Commons.
But the psychological impact of defeat could be heavy, with Brown already on the back foot after a rout in local elections three weeks ago and a backbench revolt over the abolition of the 10p starting rate of tax.
Dunwoody's 49-year-old daughter Tamsin is fighting the seat for Labour, but faces a stiff challenge from the Conservative candidate Edward Timpson, 34, who was enjoying a 13-point lead in a ComRes poll in the Independent on Tuesday.
Liberal Democrat candidate Elizabeth Shenton, 43, has also been waging a vigorous attempt to push Labour into third place.
Campaigning has been intense, with some locals complaining about the volume of party literature pushed through their letter boxes.
Conservative leader David Cameron has visited the constituency four times in the run-up to polling day.
But Brown, whose personal poll rating has slumped, has stayed away, insisting that his absence is merely due to a tradition that prime ministers do not visit by-elections.
Dunwoody's campaign has provoked controversy by playing the class war card, portraying Timpson as a "toff" supported by the fortune of his family's regional chain of key, lock and shoe repair shops.
Labour party vice-chairman Stephen Ladyman has described the tactics as "a little crude", adding that the party needs to be sharper and wittier in future campaigns.
