Ms Pritchard, NHS England's chief operating officer, will step up from 1 August.

She was previously head of Guy's and St Thomas' NHS Trust in London and an adviser in Tony Blair's government.

Prime Minister Boris Johnson said her experience and expertise made her "perfectly placed" to lead the NHS.

"I am delighted Amanda has been appointed the new NHS chief executive, the first woman in the history of the health service to hold this post," he said.

"This is a critical moment for the NHS as it continues to care for Covid patients whilst tackling treatment backlogs caused by the pandemic.

"I look forward to working closely with her."

As the prime minister said, Ms Pritchard's appointment comes at a crucial time for the NHS.

Not only does she have the coronavirus pandemic to deal with, but the government has launched a major overhaul of the NHS, which will see the creation of integrated organisations to bring hospitals and community services closer together.

She will also be responsible for navigating what many believe will be one of the NHS's toughest winters.

Coronavirus cases may be declining but the return of flu and other winter viruses on top of Covid is expected to stretch hospitals to their limit during the next six months.

Then there is the backlog in other treatments to tackle.

The waiting list for non-emergency care, such as knee and hip operations, now exceeds five million, the highest on record.

And this is expected to grow significantly because there are thought to be millions of patients who have not yet even been referred on for care.

Ms Pritchard started in the NHS as a management trainee, in the late 1990s, before holding senior posts at the Chelsea and Westminster Hospital NHS Foundation Trust.

From 2005 to 2006, she worked in the Prime Minister's Delivery Unit and spent nearly four years as Guy's and St Thomas' chief executive before becoming NHS England's chief operating officer in the summer of 2019.

In her current role she has worked closely with Sir Simon, effectively acting as his deputy.

'Big challenges'

Ms Pritchard described her new appointment as a great honour.

And she said she was "thrilled" to be the first female leader of the NHS which was "75% women".

"I have always been incredibly proud to work in the health service but never more so than over the last 18 months as nurses, doctors, therapists, paramedics, pharmacists, porters, cleaners and other staff have responded so magnificently to the Covid pandemic.

"There are big challenges ahead.

"However, the skill, determination and 'can do' spirit that NHS staff have shown in the face of the greatest challenge in the health service's history means we face the future with confidence."

Matthew Taylor, chief executive of the NHS Confederation, which represents health managers, said her appointment would be warmly welcomed.

"Amanda is the continuity candidate and her appointment ensures she will hit the ground running when Sir Simon leaves.

"This role is arguably the most significant across the entire public sector and with a new health secretary getting up to speed, this continuity at the top of the NHS will be vital."