Nationwide building society has pulled the plug on a terminally ill employee's medical care halfway through an expensive course of treatment.

The decision has left the employee facing a terminal condition without the drugs and therapy he had come to rely on to improve the quality of life of his final months.

His wife believes that the lack of treatment is due to a new focus on commerciality at the Nationwide, which ostensibly prides itself on its mutual status.

The man - whose name the Observer has agreed to withhold - was diagnosed with incurable lung cancer in mid-2006. At that time, he was working for Portman Building Society in Bournemouth. The Portman merged with Nationwide in September 2007 and, unlike subsequent Nationwide mergers with the Derbyshire and the Cheshire, the Portman name and many of its offices disappeared virtually overnight.

When the employee was first diagnosed, medical staff told him his condition meant he would have very little quality or length of life unless he received specialist care and expensive drugs. His local NHS trust refused to pay for these.

But Portman provided its employees with private medical insurance through an Axa PPP policy, which included help with advanced cancer treatments and drugs. He was booked into a leading London hospital for a seven-week course of radio and chemotherapy.

On his return home, his wife inquired about further treatment to be told that Nationwide, his new employer, offered private medical cover through rival insurer Cigna. "I was told that there would be no more treatment as the new policy did not cover advanced cancers and that 'he would be eased back into the NHS'," she wrote to the Observer

The family consulted a solicitor. "The lawyer felt Nationwide was morally in the wrong but it could well be in the right legally. I decided to take Nationwide on myself - my husband is too ill - and spent a year corresponding with it only to get nowhere. It stuck to its guns with not even a word of apology," she says.

She checked with Axa PPP, which said it would have continued to finance his treatment, including the drug Tarceva, which is not generally available on the NHS, and can cost £2,000 a month.

"Nationwide said we should have read the policy conditions. But basically, Nationwide moved former Portman staff onto an inferior, and probably less costly, policy. It never entered our minds that someone could be switched mid-treatment," she adds.

Nationwide told the Observer: "The cover provided by Axa and Cigna was broadly similar. Overall, individuals would not have been disadvantaged by the change in healthcare provider. Determination of whether an individual's case is covered is carried out on a case-by-case basis."