Cancelled operations go 'unrecorded'.

Tens of thousands of operations were cancelled by English hospitals in 2015 but not officially counted, figures obtained by the BBC suggest.

About half of trusts provided details of cancellations one to three days before admission. Hospitals must record cancellations on the day of an operation, or of admission, but not before.

Official NHS England figures show about 7.7m planned operations were carried out in England in 2015.

There were 71,370 last-minute cancellations, either on the day the patient was meant to arrive, after they had arrived, or on the day the operation was due to take place.

In each case, NHS rules say a patient should be offered a new date within 28 days. If that deadline is missed, hospitals are not paid for the operation, and it is recorded in official figures.

However, operations cancelled outside of the official definition are not subject to the same rules.

The BBC asked all 156 NHS trusts in England, via a Freedom of Information request, to provide figures for operations cancelled one to three days before a patient was due to be admitted.

Seventy-four provided data suggesting they had cancelled 41,474 operations within that period – compared with 33,400 last-minute cancellations recorded for the same trusts in the official figures.

The main reasons for cancellations were a lack of beds or ward space and staff shortages.

For operations cancelled on the day, emergencies take priority - something that can have a knock-on effect for operations scheduled for the following day as well.

Twenty-nine trusts also provided data for cancellations made by patients themselves, which, in many cases, were higher than the number cancelled by the hospitals.

An NHS England spokeswoman said: "The proportion of patients seeing their operations cancelled at the last minute remains under 1% in spite of record numbers of operations being scheduled.

"Our national data collection rightly requires trusts to focus on monitoring the number of last-minute cancellations, as this is where the most distress is caused for patients.

"Hospitals should continue to ensure that every effort is made to reschedule cancelled operations as soon as possible."

Director of policy and strategy at NHS Providers, Saffron Cordery,  said: "There are many reasons why operations are cancelled at short notice. Some may be due to poor scheduling and a lack of effective planning, but this is very often not the case.

"Increasingly, we are hearing from NHS trusts that it is often down to a more general lack of availability of critical care beds and a lack of anaesthetists and surgeons.

"It is also often down to ever-increasing emergency cases requiring theatre time that exceeds level of demand that has been expected."

Chief executive of the Patients' Association, Katherine Murphy, said: "You can't underestimate the upset for the patients, their family, their friends and everybody else if an operation is cancelled."