More than 100 patients marched from Tooting Bec station to St George's Hospital to protest the potential closure of a women's unit.
Services at the urogynaecology unit in the Tooting hospital were suspended in June, after the clinical lead stood down, meaning members of the hospital trust board were unable to guarantee patient safety.
February 4: Kingston and Sutton Councils hear the case for St George's Urogynaecology department as decision is delayed
January 29: Claims 'untrained NHS staff are treating child sex abuse victims using textbooks'
October 22: St George's Hospital urogynaecology department faced with closure after lead consultant steps down
The unit has since been recommended for closure, and protestors marched from the underground station to the hospital on Saturday morning urging the board to keep it open.
Brian Colman, south west London chairman of Keep Our NHS Public (KNOP), said: "The march showed the strength of feeling and support from the community.
"I suspect we will see a shift from them [the board].
"I think they thought they were going to slip this under the radar and they have not got away with it.
"They thought they had found an easy way out to keep it permanently closed.
"The lesson to me and I keep seeing in other trusts, is that the prime thought was if we don't reopen it, we will save money.
"The prime thought should have been what does our community and the patients need."
Organiser Sue Balding, from KONP, said: "We were joined by women from the Muslim Women's Association and several nurses who had worked at St George's, who travelled from Hertfordshire to be on the march.
"Other supporters were Wandsworth Green party, Wandsworth and Battersea TUC, local teachers and anti austerity campaigners and KONP members from South West London and from Lambeth."
Campaigners were addressed by Esther Obirir-Darko, Wandsworth Green Party London Assembly candidate, and Barbara Bohanna and Stephanie Sulaiman, St George's patients who have instructed solicitors for a judicial review of the urogynaecology department closure.
An update on the unit will be given to the Wandsworth Council health overview and scrutiny committee on Tuesday evening, while Merton Council hears from Michelle Fynes.
Miss Fynes is a consultant in the unit who has worked to keep it open by proposing an alternative nurse-led arrangement.
A spokesman for the St George's Hospital Trust said: "The urogynaecology service, which is a sub-speciality of the gynaecology service at George’s, was suspended in June 2015 on governance and safety grounds.
"We recently undertook an internal and external consultation to consider the long term provision for patients who require this service.
"The outcome of the consultation and proposed next steps will be discussed at the trust’s March 2016 Board meeting.
"The care of our patients and their safety has always been and remains at, the centre of this proposal of change."
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