Paramedics in Lancashire have announced a raft of weekly strikes as part of an ongoing and increasingly bitter pay row.
Members of the GMB union will walk out every week until at least October.
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They will strike between 6am on Saturday to 8am on Sunday every week - one of the busiest periods of the week with extra volume of calls during busy Saturday nights.
Unions bosses say they will continue their protest until they receive a "genuine commitment to find a resolution".
North West Ambulance Service (NWAS) paramedics have already staged four strikes in recent weeks after a ballot of members saw more than 84 per cent of those who responded vote for strike action.
The dispute centres around job re-evaluations which were started 13 years but from which there has been no outcome.
GMB represent more than a quarter of NWAS paramedics.
Mike Buoey, GMB organiser, said: “This is the last situation our paramedics wanted to find themselves in, but they are desperate for management to listen to their side of the story.
“They’ve been waiting a long time for their job to be re-evaluated for the years between 2005 to 2016.
“NWAS currently has an acting CEO and GMB believes he is ignoring this issue in the hope it will go away.
“We need to speak to someone with authority who shares out interest in resolving this matter.
“After more than 13 years, our members are now saying enough is enough.”
NWAS have been asked for a comment but are yet to respond.