MARK SERWOTKA will address tomorrow’s NHS demo in his first public speaking event since having a heart transplant in December.

The PCS union leader said he owed his life to doctors and nurses and would do “whatever I can to repay” them and Britain’s beloved health service.

“Our NHS is in crisis from budget cuts and a lack of resources that are plain for everyone to see,” he said yesterday.

“What is less obvious is the hardship that worsening pay is having. During my three months in hospital I met nurses, and even junior doctors, who left or were planning to leave the NHS because of it.

“These were dedicated professionals, genuinely heartbroken at feeling forced out of the jobs they loved because they literally couldn’t make ends meet.”

Mr Serwotka, who has led the civil servants’ union for 17 years, was fitted with a special defibrillator pacemaker in 2010 after a mysterious heart failure. It is thought he picked up an infectious disease when washing down his dog after it had rolled over a dead fox.

After he was told that his weak heart would mean a transplant was likely to fail, he was fitted with a ventricular-assist device to pump blood round his body in a risky operation.

“I’m the only Duracell-powered general secretary in the labour movement,” he quipped at the time.

His transplant was finally carried out in December at Papworth hospital near Cambridge.

“I’m marching because the political issues are as urgent and important as anything we’re facing right now,” he added. “But for me, it is also intensely personal.”