Junior doctors have voted to strike for 72 hours in March, in a walkout that is expected to hit every hospital in the country.About 98 per cent of those balloted voted in favour of the action, which represents a dramatic escalation of the pay row between NHS staff and the government.With more than half of all junior doctors in England covered by the vote, it leaves the health service facing “enormous” challenges, with leaders “deeply concerned” about how patients will be cared for.