A government health minister has attacked NHS plans that could see the closure of the Accident & Emergency and maternity wards at St Helier Hospital in his area.
Paul Burstow, Liberal Democrat MP for Sutton and Cheam said the plans "lack reality" and should not go ahead.
The Labour Party has called his criticism "hypocritical".
The proposals for south London would be subject to a 12-week public consultation expected in the autumn.
'Whiff of hypocrisy'
The NHS "Better Services Better Value" review recommended the number of A&E departments in south-west London be reduced to improve efficiency.
Last week a Scoring Panel of 60 local people, managers and GPs decided that St Helier Hospital should lose its A&E and maternity departments, but have a planned centre for elective surgery.
Services would be transferred to Croydon and Kingston Hospitals.
But Mr Burstow, who was born at St Helier, said talk of it taking just an extra six minutes to get to Tooting, Croydon or Kingston from Sutton were "inaccuracies" and an example of the "lack of reality" being "foisted into the process" by the NHS locally.
He has said the review was initiated by the local NHS, not by the Department of Health.
Shadow Health Secretary Andy Burnham said: "It comes to something when a health minister is launching a campaign against the impact of his own policies on the ground in his own constituency."
He said there was a "whiff of hypocrisy" about it and added: "If it's not good enough for Paul Burstow's constituency then it's not good enough for any constituency."
Mr Burstow said the Primary Care Trust, overseeing the plans for St Helier, did not have the "legitimacy" to make these decisions and was part of the government's reasons for reform of the NHS.
Dr Howard Freeman, Joint Medical Director, South West London NHS, said: "If and when we go out to consultation everyone who lives in south-west London will have their opportunity to respond to that consultation.
"It's too early for people to start campaigning to save their A&E when no decision has been made."