Hospital operations were repeatedly suspended after a surgeon found blood on surgical instruments he was about to use.

General surgeon Mr Simon Stock pulled out of planned surgery at Bishop Auckland General Hospital after he discovered the dirty instruments.

In total, Mr Stock cancelled four operations at the hospital over four months.

The equipment had been supplied by the area's central sterilisation unit at Darlington Memorial Hospital.

Bishop Auckland's own sterilisation unit was closed as part of national guidelines on centralising resources.

Managers at South Durham Health Care NHS Trust said they have now stepped up sterilisation techniques.

Confidence dented

Head of estates at South West Durham Health Care NHS Trust, Kevin Oxley said Mr Stock's confidence in the service was dented after he found instruments were dirty before he came to operate, causing him to suspend the procedure.

But the problem had been spotted before surgery started.

Mr Oxley said: "This is not ideal and we recognise this, but patients were not put at risk.

"Since then we have stepped up procedures in the department."

The problem was that instruments were not immediately dipped after surgery and when blood dried on them, it was baked on to the metal during the cleaning process, he said.

In future, instruments would be dipped immediately after use, Mr Oxley said.

Since the problem was highlighted and improvements made, Mr Stone has been reassured and has started carrying out non-emergency operations again, Mr Oxley said.

Mr Stone had always continued to carry out emergency procedures.

Mr Oxley added: "To put it in context, there are two million instruments sterilised every year at the service and there are a series of quality checks that go on."