The number of elective operations cancelled at the last minute by NHS trusts across England is at a 15-year high - while an increasing number of patients are waiting more than a month for the procedure to be rescheduled.
The latest figures released by the health service shows that 21,249 elective operations were cancelled at the last minute in December for non-clinical reasons such as staff and bed shortages or administrative errors.
This was up by 2,856 for the same month in 2015, and represents 1.1 per cent of all elective activity - up from 0.9 per cent.
For 2016 as a whole, a total of 82,730 planned procedures were cancelled - a jump of 16 per cent on the year before, and the highest level since 2001.
Of these cancellations, 1,551 - or 7.3 per cent - of patients had to wait more than 28 days to be treated.
This is up from 1,092, or 5.9 per cent, of patients in December 2015.
The president of the Royal College of Surgeons, Clare Marx, said such cancellations were "heart-breaking" for patients - and warned these last-minute delays, which refer to operations called off on the day patients are due into hospital, were the "tip of the iceberg".
The top 10 trusts for cancellations:
Leeds Teaching Hospital NHS Trust cancelled the most elective operations, with 542 - 82 of which were not rescheduled for within 28 days.
United Lincolnshire Hospitals, Plymouth Hospitals, University Hospitals of North Midlands, and Central Manchester University Hospitals NHS trusts were also in the top five.
Meanwhile, Suffolk Community Healthcare, Nuffield Health Cambridge Hospital, Derbyshire Community Health Services, Cambridgeshire Community Services, Birmingham Community Healthcare, Gloucestershire Care Services, Dorset Healthcare University and Somerset Partnership NHS trusts all reported zero last-minute cancellations.
Non-clinical reasons for procedures being cancelled include:
Ward beds being unavailable
Surgeon being unavailable
Emergency cases needing the theatre
Theatre list over-running
Theatre staff unavailable
Critical care bed not available