Labour has pledged to outspend the Tories by investing an additional £26 billion in the NHS to rebuild “crumbling” hospitals and improve patient care if the party wins the General Election.

Shadow chancellor John McDonnell said his party was offering an annual average 4.3% real-terms increase in health spending over the next four years, which would be used to drive down waiting times and drive up performance.

He claimed the Tories were only proposing to spend 3.3% extra a year, accusing Boris Johnson’s party of making “weak commitments” which reflected their “hostility to free public services”.

But Health Secretary Matt Hancock claimed Labour’s plan for a four-day week would cost the NHS a fortune, and said the Tories would “always ensure the NHS is there for you and your family”.

Announcing the plans alongside shadow health secretary Jonathan Ashworth, Mr McDonnell said they would take the total Department of Health and Social Care budget to £178 billion in 2023-24.

“On each of these fronts, the Tories have offered weak commitments, reflecting their hostility to free public services and the need for us to care for each other,” he told a Labour campaign event in London.

He said they appeared to be on course for “the worst winter the NHS has ever endured”.

“The NHS is in crisis under the Tories. Labour is the party of the NHS. We are the creators of that jewel in our crown,” he added.

Mr Ashworth said the investment plans, which were “more than the Tories are offering”, would mean an increase in funding for primary and secondary care services.

“We will invest more to relentlessly drive up performance and drive down waiting times. We are determined to see expected standards of care enshrined in the NHS constitution met…

“Patients should not be told they have to wait longer and longer in pain and distress as they are under the Tories, especially cancer patients when we know cancer waits for no-one.

“Long waits risk a person’s health deteriorating further. It is shameful.”

He said the NHS would be “literally rebuilt under a Labour government” as he pledged to commit an additional £15 billion capital investment to rebuild “crumbling hospitals”.

“Overall NHS capital expenditure – budgets that have been cut under the Tories and raided – will increase to meet the OECD average and it will be done through public investment.

“That will mean an extra £15 billion capital investment to rebuild crumbling hospitals and invest in the cutting-edge medical technology of the future.

“Years of Tory cuts to capital budgets have left our NHS with a £6.5 billion repair bill – we will clear the maintenance backlog. The NHS will be literally rebuilt under a Labour government.”

The Liberal Democrats said the announcement “misses the point” as Brexit has “already cost the economy as much as £66 billion”.

“If (Jeremy) Corbyn had not tacitly supported Brexit, Labour could have funded their NHS plan more than two times over,” the party’s health spokeswoman Luciana Berger said.

But Nuffield Trust chief executive Nigel Edwards said the funding would mean the NHS could “breathe a sigh of relief”, adding: “A 4% increase a year will make a big difference compared to the 1.4% average the NHS has grown used to in recent years.”

Richard Murray, chief executive of The King’s Fund, said: “The success of any NHS funding policy will rest on the ability to recruit and retain enough workers to staff NHS services.

“Labour’s pledge to reinstate a training bursary for nurses is welcome, although it will be critical to focus on retaining existing NHS staff over the next few years, at a time when many are leaving the service due to the intensity of their workload.”

Dame Donna Kinnair, chief executive and general secretary of the Royal College of Nursing, said all parties need to commit to investing in nursing, adding: “No matter how people voted in the EU referendum, nobody wants the NHS left open to a carve-up as a result of a post-Brexit trade deal.

“Brexit chaos and rows about deals cannot become a distraction from solving the mounting nurse shortage at home.”