A Norfolk MP has told parliament 20 people died in instances when ambulances arrived late to emergencies during a spell of intense pressure over the Christmas period.

Clive Lewis told the House of Commons a whistleblower had come to him with the shocking claim after 12 days of increased levels of calls.

The whistleblower alleged that senior operations managers wanted to move the East of England Ambulance Service to the highest state of alert on December 19 but a final decision was not made until New Year's Eve.

The Resource Escalation Action Plan (REAP) – which has four levels – was finally enacted although bosses decided against calling in help from elsewhere which could have seen the military answering 999 emergencies.

Raising a point of order the Norwich South MP said: 'I hope to get your advice on an exceptionally serious issue that's been brought to me by a whistleblower in my constituency relating to the East of England Ambulance Service.

'It has been put to me that the service became critically over-stretched due to high demand on December 19, and at that point senior operational managers wanted to move to REAP 4, the highest state of emergency, and seek mutual aid, most likely from the armed forces.

'However, that decision was not taken until 31 December, some 12 days later, and even then aid was not requested by senior management.

'I've been informed during this period that 20 people died in incidents where ambulances arrived late.'

It is not known whether the number stated by the whistleblower is for the whole eastern region or just Norfolk.

A spokesman at East of England Ambulance Service Trust said: 'We recognise that some people experienced a delay in their care over the festive period and we, along with the wider health care system, experienced significant pressure.

'We always monitor our demand and capacity and take necessary actions to protect patients. The trust has a robust internal process and we are investigating appropriately. Since Christmas we have responded to in excess of 50,000 patients – less than 0.2pc of patients have experienced a significant delay.'