Mary Waterhouse had been complaining about her knee for years and, with a history of arthritis, was fairly certain what was causing the pain. “Sometimes my knee won’t straighten, other times it won’t bend,” the 72-year-old from Blackpool tells i . “It’s very, very swollen.

By the time they took an X-ray of it there wasn’t really anything they could do, other than give me painkillers, as the arthritis had set in. That was in January 2022.” Mary’s knee problems begun to affect her gait, which had a knock on effect on her hip, so she needed steroid injections to help her manage.

A subsequent MRI revealed a trapped nerve in her spine and was referred to a specialist, who said surgery would not help and referred her back to the orthopaedic clinic. Last July she was finally referred for a knee replacement, joining the millions of patients on the ballooning NHS waiting list for non-urgent treatment. The size of the list, a symptom of the chronic state of the National Health Service in general, has become a key battleground in the general election campaign.

Rishi Sunak was dealt a further blow in his bid to stay in No 10 this week when the latest NHS England figures revealed the waiting list had grown again for the first time in seven months . Some 7.57 million treatments waiting to be carried out at the end of April, relating to 6.

33 million patients, a rise of 40,000 people from the previous month. In January 2023, when Mr Sunak had pledged to reduce waiting times.