The Opposition leader is travelling to the Hampshire town where the Lib Dems are engaged in a fierce battle to prevent their Tory coalition partners snatching the seat.
Labour is hoping for a good showing in the contest sparked by the resignation in disgrace of ex-cabinet minister Chris Huhne after he admitted dodging a speeding penalty.
But despite recruiting best-selling author and satirist John O'Farrell as its candidate, insiders acknowledge it has no realistic chance of winning on February 28.
Mr Miliband will use his visit in a bid to capitalise on his surprise announcement yesterday that Labour favoured reviving the 10p income tax rate.
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The Labour leader did not say whether he would maintain Britain's nuclear deterrent programme.
Ukip leader Paul Nuttall also said he would want to get rid of Sharia courts.
Over 40,000 people picked up their packs to take part in the annual marathon in the capital.