Assura, a UK healthcare property investor and developer, has struck a £500m deal to buy Canada’s Northwest Healthcare Properties’ portfolio of 14 private hospitals across the UK, including Cancer Centre London and the Edgbaston hospital in Birmingham.

The deal comes at a time when the NHS is under massive pressure, with near-record waiting lists. The NHS crisis is prompting more people to go private, either paying for treatment themselves or taking out insurance. To clear the backlog, the NHS has been outsourcing more procedures, including cataract surgery, to private clinics.

The hospitals are spread throughout the UK, and are let on long leases to a number of private healthcare providers. They include six Nuffield hospitals including Woking, Edinburgh, Highgate and Cancer Centre London; five Circle hospitals, including Huddersfield, Lancaster and Lincoln; two Spire hospitals, Cheshire and Claremont; and the Edgbaston hospital in Birmingham run by Practice Plus Group, which is closed but due to reopen in September after renovation.

Assura said the three main strands of private healthcare – insurance, self-pay or NHS referrals – were all experiencing growing demand. Top procedures include cataract surgery, chemotherapy, diagnostics, such as endoscopy and colonoscopy, and orthopaedics, typically hip and knee replacements, which are procedures well suited to day-case units.

The company said: “The NHS system remains under considerable strain. Private providers help ease local pressure on waiting lists.”

The NHS waiting list in England reached a peak of nearly 7.8m last September and is still at 7.6m cases, of about 6.38 million patients, some of whom need several procedures. About 3.1 million patients have been waiting for more than 18 weeks.

In late May Labour promised to clear the NHS waiting list backlog in England within five years, if elected. Wes Streeting, the health secretary, has said the health service risks becoming “a poor service for poor people” while the wealthy shift to using private care.

Assura pointed to research from YouGov that showed eight in 10 of people who used private healthcare last year would previously have used the NHS, and research from the Care Quality Commission that showed that 56% of people had tried to use the NHS before opting for private care.

Jonathan Murphy, the Assura chief executive, said the deal “means we now have relationships with all tier 1 private healthcare providers. This represents a unique opportunity to participate in the growing demand for private healthcare services to help ease growing NHS waiting lists amidst the ongoing UK healthcare crisis.”

Oli Creasey, a property analyst at Quilter Cheviot, said: “The transaction is genuinely transformative for Assura’s portfolio, which up until now has been dominated by NHS-run GP surgeries, typically associated with a low rate of rental growth. The hospitals have a longer unexpired lease length of 26 years and rent growth is index-linked, which should increase the portfolio rental growth rate in future years.”

Assura’s current portfolio is worth £2.6bn and the deal increases its size by almost 20%. The transaction is largely debt-funded, but Assura plans to make some disposals in its portfolio to pay down some debt.

To fund the deal, the company plans to issue £100m in shares to Northwest, refinance £266m of debt, draw down £80m from its revolving credit facility and use £54m of cash.