The poll carried out for campaign group 38 Degrees by Survation found 17% of Brits had paid privately for healthcare for themselves or for a dependant within the last year.

Matthew McGregor, chief executive officer at 38 Degrees, said: 'The polling shows most people who turn to private healthcare aren't doing so because they don't want to use the NHS. In fact, most of them are NHS patients, people who've paid in throughout their lives and were promised cradle-to-grave care, but find the service is no longer there for them when they need it.'

In further findings, 15% said they had accessed NHS and private treatment, while just 2% had only used private healthcare.

Over a third (37%) of people said they had sought private healthcare because of long NHS waiting lists, with almost a quarter (23%) saying the treatment they needed wasn't available on the NHS.

Treatment accessed privately included elective inpatient care, such as surgeries (16%), outpatient care such as tests (25%) and mental healthcare (19%). Primary healthcare was the most common type of healthcare among both NHS and private patients but represented a much larger proportion of the NHS care received (76% of NHS patients compared to 41% of private patients).

Over a third (36%) of patients paid £500 or less for treatments with a similar amount (35%) paying over £1,000 for their care.

More than one in five (22%) had gone into debt to fund their care, while 39% found the cash from their savings, 13% had to borrow money from family or friends and 9% took out a loan.

The figures were published as 38 Degrees called on all parties to offer real solutions to the NHS crisis ahead of the General Election.