New laws are needed to stop union barons who put ‘lives at immediate risk’ by failing to provide enough timely cover during ambulance worker strikes, the Health Secretary has said.

In a letter to the GMB union, Steve Barclay said ‘voluntary arrangements’ put in place ahead of recent walkouts were too last-minute and not enough to ‘ensure patient and public safety’.

He said it showed that new strike laws designed to ensure a minimum level of services run during ‘blue light’ strikes are desperately needed.

MPs are expected to clash over the legislation when it is debated in Parliament today, with Labour vowing to block it despite warnings that doing so could put lives at risk.

It came as the Royal College of Nursing (RCN) union warned that nurses’ strikes in England on Wednesday and Thursday will be the biggest yet. Staff across 55 trusts are taking part – 11 more than during the union’s December walkouts.

Yesterday, RCN boss Pat Cullen warned she was prepared to carry on the strikes for up to a year. Pickets will stay ‘for as long as it takes for this government to do the right thing for nursing staff’, she told The Sunday Telegraph.

Mr Barclay is said to have privately acknowledged that nurses deserve more money, but has been told by Chancellor Jeremy Hunt that any improved settlements must be found within his department’s existing budget.

Nurses have been offered the equivalent of 4.5 per cent for 2022-23, but the RCN initially demanded pay rises of 19 per cent. It has since suggested 10 per cent would be enough.

Thousands of ambulance workers who are members of the Unison and Unite unions will strike again next Monday.

In his letter to the GMB, which also represents ambulance staff who went on strike last Wednesday, Mr Barclay said a ‘certain amount of disruption is inherent to any strike’. But he argued that anti-strike legislation was required to stop putting so many lives at risk.

The letter, dated yesterday, added: ‘During recent action I have not been reassured that the current system of voluntary arrangements can be relied upon to ensure patient and public safety.

‘While all unions involved in the recent strikes agreed to coverage of category 1 calls [for life-threatening situations], not all agreed derogations for coverage of all category 2 calls, which includes serious conditions such as a stroke or chest pain... In addition, assurances I have received from trade unions covering ambulance services in particular have been volatile, with the scope and extent of arrangements being disputed right up to wire.’

Mr Barclay said the legislation, called the Strikes (Minimum Service Levels) Bill, will give the public ‘much needed assurance that a certain level of urgent and time-critical care will always continue throughout strike action’.