Hospital doctors in England on Friday launched their latest walkout as the government said their strike to demand a 35-percent pay increase served “only to harm patients”. The four-day stoppage comes with health chiefs estimating that the repeated industrial action had cost the publicly funded health service £1 billion ($1.2 billion). Junior doctors — physicians who are not senior specialists but who may still have years of experience — make up about half of the doctors in UK hospitals. Their fifth round of industrial action began at 7:00 am (0600 GMT) and is scheduled to run until 7:00 am on Tuesday. Health Secretary Steve Barclay issued his strongest condemnation so far of the doctors who have rejected the government’s pay offer of six percent plus a one-off payment of £1,250. Writing in the Daily Mail, he accused the British Medical Association (BMA), which represents junior doctors, of “acting recklessly”. The strike action served “only to harm patients and put further pressure on their own colleagues”, he added. Doctors on a picket line outside a central London hospital, however, said they had no choice but to strike and accused the government of refusing to negotiate. “Doctors are working tirelessly to bring waiting lists down. The government are the ones who refuse to come to the table,” said junior doctor Sumi Manirajan.