Only one GP was on duty covering Wisbech and Norfolk on at least three weekend days throughout January a population of more than 900,000- an investigation by this newspaper has revealed.

The information was included in staff rotas for service providers Integrated Care 24 (IC24), provided to us by an NHS whistleblower.

The documents also provide a snapshot picture of an out-of-hours home-visit list which shows that on one day the service had breached maximum waiting times for 11 of 25 patients.

There are also several unfilled GP shifts during the day on Saturdays and Sundays.

Former health minister Norman Lamb has called for an urgent and unannounced inspection of the service after he was contacted by a separate whistleblower.

He said: “If these issues are true then that’s not acceptable and they have to be resolved straight away.

“This is potentially about life and death.”

Mr Lamb has written to health watchdog the Care Quality Commission (CQC) urging them to carry out an unannounced inspection.

The whistleblower claims “patient safety is not a priority” and that a severe shortage of GPs working in the service in causing excessive hours of waiting for patients.

We put the figures provided by our source to officials at IC24, but they did not respond directly to these.

Instead, we were provided with a copy of a letter sent to IC24 staff by chief executive Yvonne Taylor.

She said it was committed to delivering an integrated urgent care service which is GP-led and in line with NHS England’s vision.

The controversy comes five months after IC24 began providing the NHS 111 and out-of-hours GP services following a handover by East of England Ambulance Service Trust.

Last month a report by Norwich Clinical Commissioning Group, which awarded the contract to IC24, concluded the CCG was not clinically assured of the safety of the services.

In its report, the CCG said it had been made aware of occasions when “only one or two GPs were available for Norfolk and Wisbech”.

In addition, new official figures show an increase in the number of 111 calls that resulted in an ambulance response since IC24 took over the contract.

This has fuelled fears that patients left waiting by the 111 and out-of-hours GP services are dialling in 999 in desperation for help. Our source, a medical worker who also worked for out-of-hours GP service when it was provided by the ambulance trust, warned “patient safety is not a priority at IC24”.

The source said: “Patient waiting times being breached is a common occurrence.”

According to the source, there used to be up to four out-of-hours GPs working overnight based in Norwich, Thetford, North Walsham, and King’s Lynn, when the service was provided by the ambulance trust.

But the rotas suggest IC24 is struggling to fill overnight GP shifts at Norwich and Thetford, while shifts at King’s Lynn are covered by advanced nurse practitioners or emergency care practitioners (ECP).

These medical staff do not have the same levels of training, expertise, and ability to dispense drugs as GPs.

The source alleged IC24 is hiring paramedics, some of whom have limited training and experience in primary care.

The source said: “For example ECPs hold recognised primary care qualifications and were trained in GP surgeries, whereas paramedics’ experience is mainly in emergency care.”

In response IC24 said in its letter it was changing the staff’s skill mix from a GP workforce to a “broader skill mix best able to meet the needs of the patients”.

Meanwhile the source warned excessive waiting times were forcing patients to seek help by calling 999 instead.

And figures revealed the monthly average ambulance emergency responses seen in Norfolk when the ambulance trust operated the service was 852 per month, only for this to rise to 1,015 since IC24 took over.

Mr Lamb added: “Anthony Marsh (former chief executive of the ambulance trust) raised concerns with me about this when he was chief executive and we have to take note of these concerns.”

In her internal letter to staff, used by IC24 to respond to this newspaper’s questions, Yvonne Taylor said: “The new service is not the same as that previously delivered with a different model and geography.

“We are tasked with delivering an integrated urgent care service which is GP-led.

“The service model that CCGs have commissioned is completely in line with NHS England’s Vision for Transforming Urgent and Emergency Care services in England.

“We have developed a new GP oversight role to work clinically across 111 and out-of-hours to support clinical decision-making and reduce access times for patients who need to be seen face-to-face.

“We have been and continue to recruit paramedic practitioners who function within our organisation. These staff have additional training in clinical assessment, minor illness, and the competencies necessary for the roles they are fulfilling.

“We have put a number of things in place to support all staff – staff meetings, senior management visibility, chief executive officer open-door session (by phone or in person).

“We are also absolutely committed to being open and transparent about the challenges we face with CCG colleagues, MPs, as well as the press.”

She said she and IC24’s chairman Judy Oliver will visit bases in Norfolk this week.