AN NHS boss is to be quizzed over a controversial unauthorised experiment that led to ambulance delays for up to 20,000 patients.

Under-fire South East Coast Ambulance Service NHS Trust chief executive Paul Sutton will be speaking to members of the West Sussex health and adult social care select committee next week.

Health sector regulator Monitor has said the pilot project, which involved the ambulance trust changing how it handled some NHS 111 calls, was poorly handled.

It is now running an investigation into what happened.

NHS England has also criticised the trust for acting “unilaterally” and not following proper procedures when setting up the project.

The cases stemmed around urgent cases transferred from the NHS 111 line to the emergency 999 service.

National rules state 75 per cent of Category A Red 2 calls should have an emergency response at the scene within eight minutes.

These calls are for conditions regarded as serious such as strokes or fits.

Under the project, the ambulance trust gave itself up to 10 extra minutes to reassess what type of advice or treatment patients needed, and whether an ambulance was really necessary.

However, patients were kept in the dark about the scheme, as were 111 call handlers and the trust's board.

The trust said the move was carried out last winter at a time when it was under extremely high demand and it would never do anything to deliberately put patients at risk.

However it recognised the proper processes were not fully followed in setting up the project and has apologised for this.

Committee chairwoman Margaret Evans said: “The committee’s role is to review and scrutinise health and adult social care services, focusing on making sure services are effective, safe and deliver high quality outcomes and experience for local people.

“We are concerned about Monitor’s findings about South East Coast Ambulance’s pilot project and want to hear whether any West Sussex residents were negatively impacted.”

The ambulance service project is on the agenda at the scrutiny committee meeting at County Hall in Chichester on December 4 from 1.30pm.

The ambulance part of the meeting will be webcast via the www.westsussex.gov.uk.