Nurses are staging a second walkout in four London hospitals in a row over pay as a series of strikes hits the UK in the run-up to Christmas.Around a quarter of hospitals and community teams in England are taking part in the strike, alongside all trusts in Northern Ireland and all but one health board in Wales.In London, strike action is underway at Guys’ and St Thomas’ NHS Trust, Great Ormond Street Hospital for Children NHS Foundation Trust, Imperial College Healthcare NHS Trust, Royal Marsden NHS Foundation Trust and the North Central London Integrated Care Board.The strikes last week saw around 1,400 procedures and operations cancelled. Imperial College Trust warned patients that their treatment may take six weeks to reschedule.