RCM members were among 400,000 NHS workers who took part in the four-hour long strike from 7am to 11am this morning, in a dispute over pay.
The walkout will be followed by four days of work-to-rule from Tuesday.
The RCM said 82.2 per cent of its members voted to say they were prepared to take part in the strike.
Striking staff said the Government's refusal to implement an across the board one per cent pay rise for all staff members means they are taking a real terms pay cut.
Health Secretary Jeremy Hunt has defended the pay offer made to NHS workers and said that a one per cent pay rise as requested by the unions would lead to job losses.
"They are working very hard, there is a lot of pressure on the front line," he said. "We are giving a one per cent pay rise to everyone, but around 55 per cent of NHS staff get an automatic three per cent pay rise through their increments, and what we're saying is we can't afford to give a one per cent pay rise on top of the three per cent.
"And that's for the very simple reason that we have very clear analysis that says if we did that hospitals next year would lay off around 4,000 nurses and around 10,000 nurses the year after that - and that would be very very dangerous for patients.
"So reluctantly we decided the responsible thing would be to give the one per cent to everyone, but not to people who are already getting that through their increments."
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