Junior doctors from St George's in Tooting went on strike for the first time in 40 years as contract negotiations failed again with the Government.
The British Medical Association (BMA) called off planning strikes in December, re-entering talks with the Department of Health on the proposed contracts for junior doctors.
January 5: Junior doctor strike back on after negotiations with government flounder
Those second talks broke down on January 4, leading to the announcement of further strike action which took place on Tuesday.
The BMA said it still had concerns over safety, pay progression, pay for all work done, and plain time versus premium time.
Sophie Herbert, one of the junior doctors at St George's, said: "We are striking because the Government has failed to offer meaningful negotiations on an unsafe contract.
"We are already at breaking point.
"We cannot do any more than we are already doing."
Ms Herbert said she hoped future planned strikes can be cancelled and that she and her colleagues can return to work, with new contracts.
She said: "People have been really positive, they have come to stop and talk to us.
"Patients are supporting us which is really reassuring."
Ms Herbert started her university career as an English Literature student but changed to medicine after realising how passionate she was about the NHS.
She said: "I had medical students friends and I realised I really loved it.
"At school I always thought it would be very difficult, but I realised I loved it and wanted to help people.
"I just want to get back to my job."
Throughout the last few months, St George's junior doctors have been running 'Meet the Doctors' stalls throughout Tooting to meet patients and gather support.
Alex Trevatt, Sophie Herbert and Richard Sykes protest at the hospital
According to Health Secretary Jeremy Hunt, 15 of the 16 areas of dispute were resolved, with an agreement to be "flexible" over pay for weekend working.
A letter from Mr Hunt, MP, to Dr Mark Porter, chairman of the BMA, said: "I was very disappointed to hear of the decision by the BMA to initiate strike action.
"In particular, it is extraordinary that you have done so without fully considering the revised offer that my negotiators presented to you this morning which you refused to talk about during negotiations today [January 4].
"I believe we made good progress in the negotiations and given the many areas of common ground it cannot be appropriate to put patient safety at risk with a series of potentially damaging strikes without seeing these negotiations through in full."
Junior doctors provided emergency care only between 8am on Tuesday and 8am on Wednesday, January 13.
The next strike, which will begin on January 26 at 8am, will run for 48 hours, where only the emergency level of care will be provided by junior doctors.
A full walkout from 8am until 5pm is scheduled for February 10.
St George's Hospital advised patients that any changes to appointments would be confirmed in writing before the strike.
A statement on the trust's website said: "St George’s overriding concern and obligation is to provide high quality and safe care to patients during this time.
"We are, as you would expect, taking the appropriate measures to ensure that services and the quality of patient care we provide are not compromised."
The hospital has not given out any details of appointments or services that have had to be cancelled as a result of the industrial action.
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