text: Labour argues that Kettering General Hospital could lose services, but this has been rejected by the Conservatives, Liberal Democrats and UKIP.
  In Parliament, David Cameron said Labour was not telling the truth.
  The NHS has told the BBC the hospital will not be downgraded.
  An NHS consultation has started into the organisation of five hospital and clinical commissioning groups, in Northamptonshire, Milton Keynes and Bedfordshire.
  The hospitals included in the review are Kettering - which is used by people living in Corby - Northampton, Milton Keynes, Luton and Dunstable, and Bedford.
  The review looks at the option of providing "specialist centres for some services where this will improve quality".
  At Prime Minister's Questions, Conservative MP for North West Leicestershire Andrew Bridgen asked the prime minister about concerns that Labour was running a negative campaign over the future of Kettering hospital.
  Mr Cameron said: "Labour MP after Labour MP is trouping up to Corby and claiming this hospital is not safe and they know this is simply not true.
  "This hospital is being invested in by this government, unlike the party opposite."
  On a visit to the constituency on Tuesday to support Labour candidate Andy Sawford, shadow health secretary Andy Burnham said: "You clearly can't believe a word the Tories say on the NHS.
  "Here in Corby and East Northamptonshire, ministers have failed to provide all the details about plans to downgrade services at Kettering.
  "Local people should be given all the facts."
  The United Kingdom Independence Party candidate Margot Parker said: "I live in the constituency. I live next to a nurse. I speak to local people. We know there is no truth in this at all.
  "It is political football of the worst kind. It is a shabby load of nonsense and scaremongering."
  Jill Hope, who is standing for the Lib Dems, has described the claims as "totally irresponsible", while Tory candidate Christine Emmett has said she has received assurances about the future of the hospital.
  The by-election was sparked by the resignation in August of sitting Conservative MP Louise Mensch.
  Mrs Mensch, who won the seat at the 2010 general election, announced she was standing down for family reasons.
  A date has yet to be set, but the by-election will almost certainly be on 15 November to tie in with the police and crime commissioner elections.
target: The prime minister has entered a row between Corby by-election candidates over the future of a hospital, amid claims it could be downgraded in a healthcare review.