The number of people waiting for NHS hospital treatment could reach 13 million in the months to come due to the COVID backlog, the health secretary has said.

Sajid Javid claims “shocking” government modelling indicates the current waiting list of 5.3 million people could more than double by the end of the year.

This includes up to seven million people who failed to attend hospital during the peak of the crisis for fear of catching coronavirus, he said.

“What shocked me the most is when I was told that the waiting list is going to get a lot worse before it gets better,” he told The Sunday Telegraph.

“Hearing that figure of 13 million, it has absolutely totally focused my mind, and it’s going to be one of my top priorities to deal with because we can’t have that.”

Current NHS waiting lists in England are the longest they have been since 2007.

Experts in cancer, stroke and heart disease care have consistently warned their fields are being ignored, while COVID-19 takes precedent.

But Mr Javid told the Telegraph he is “not just the COVID secretary of state” and that he plans to outsource treatment to private hospitals and increase the use of virtual appointments to help deal with the backlog.

He warned the lists will “take some considerable time to clear”, partially because of the “very British” attitude of those who didn’t want to burden the health service by presenting with symptoms during the first and second waves.

Mr Javid also confirmed reports that the NHS COVID app could be tweaked to reduce high numbers isolating after being ‘pinged’.

The minister said the government is looking at the possibility of “treating people differently based on whether they are vaccinated or not”.

It comes as separate reports claim ministers are trying to half the gap required between vaccine doses.

The Times reports that Number 10 has asked the Joint Committee on Vaccination and Immunisation (JCVI) to launch an urgent review into the current eight-week gap.

Politicians and scientists are desperate for as many jabs to be administered as possible amid the spread of the more-contagious Delta variant.

At Wembley ahead of the England-Italy Euro final on Sunday, the NHS is urging fans to get vaccinated at the same time if they haven’t already.

Professor Stephen Powis, national medical director of NHS England, said: “The vaccine is England’s best defence, protecting yourself, your family and your loved ones against COVID, so be a team player and get both your vaccinations in what is a game of two jabs.”