Thousands of nurses are on strike in a dispute over pay as the head of the nursing union said patients do not get safe staffing levels “any day of the week” in the NHS.Staff from more than 55 NHS trusts in England are taking part in industrial action on Wednesday and Thursday following two days of action in December.The Royal College of Nursing (RCN) has announced that two further, bigger strikes will be held next month, while the GMB union also confirmed further ambulance worker strikes on Wednesday afternoon.