Patients suffering from thyroid conditions are being routinely abandoned to gain weight because NHS bosses refuse to pay for unnecessarily expensive life-changing drugs, a report has found.

An investigation commissioned by the Department of Health and Social Care reveals potentially thousands of patients are being left to battle excess weight as well as diabetes, depression, heart problems and a range of other symptoms because of the back-door rationing.

Between one and two in every 100 people in the UK suffers from an underactive thyroid, known as hypothyroidism, an endocrine system disorder where the thyroid gland does not produce enough of the hormones needed to regulate metabolism.

Around 20 per cent of these require liothyronine, which costs less than 16p per pill to manufacturer but which until last year the NHS had been paying £9.22 for.

The new report found evidence that local healthcare commissioners are refusing to pay for the medication, despite national guidance stipulating that they should.

It means patients are being forced to endure the life-changing consequences of untreated hypothyroidism or pay for the drug themselves.

Lord Hunt of Kings Heath, who campaigns for better treatment for thyroid patients, said: “It’s not acceptable that vulnerable people are getting caught up in something that should have easily been avoided."