Union leaders have complained that more than 100 health trusts in England are 'stubbornly' refusing to afford enhanced pay rates to employees working on the day of the royal wedding.
A study completed by Unite has found that 115 NHS trusts have warned nurses and other staff they will receive normal pay rates for working on April 29.
Meanwhile the union said their counterparts in Scotland, Wales and Northern Ireland will all be paid the correct bank holiday rates, ranging from an additional 60% of pay to double their normal salary.
Unite officials say this refusal to sanction extra pay for the day of the royal wedding goes against the government's decision to make it a bank holiday.
Unite national officer, Rachael Maskell, said: "The government has given the country an extra day's bank holiday to mark the royal wedding but NHS trust chief executives on six figure salaries are refusing to recognise the spirit of the occasion. These trusts still have time to do the right thing and recognise the valuable contribution NHS staff make to this country."
Under the national agreement for the NHS, called Agenda for Change, staff working a bank holiday are entitled to enhanced pay, ranging from double to time plus 60%, Unite said.
Dr Peter Carter, Chief Executive of the Royal College of Nursing (RCN), said the findings showed yet another example of a lack of consistency across the NHS.
"It's really odd that staff in one of the four countries of the UK are not getting the same benefit as those in the other countries," he said.