More than 20,000 operations were cancelled at the last minute by NHS hospitals in England during the last quarter, the worst performance in a decade.
Figures released by NHS England show that 20,464 operations were cancelled at the last minute for non-clinical reasons from January to the end of March. During the same period in 2013/14 there were 17,868 cancelled operations.
It is the highest number since the last quarter of 2004/5, when patients saw 21,500 operations cancelled.
When a patient's operation is cancelled by the hospital at the last minute for non-clinical reasons, the hospital should offer another date within a maximum of 28 days, or fund the patient's treatment at the time and hospital of their choice.
But figures show that nearly one in 10 (8.7% or 1,787) patients did not go on to be treated within the pledged time.
This was the highest figure since the first quarter of 2005/06, when 1,959 were not treated within 28 days.
Plymouth Hospitals NHS Trust cancelled the most operations - 648 - followed by Hull and East Yorkshire Hospitals NHS Trust, with 526.
A handful cancelled none.
An NHS England spokesman said: "Cancellations should be avoided wherever possible as we recognise the concerns that patients face when this happens.
"However, the level of cancellations in this quarter has remained low in the context of the millions of operations performed in the NHS each year, and the unprecedented level of demand we have seen across the whole health system this winter."