Staff who train 999 call handlers will also walk out on Tuesday 23, Thursday 25, Monday 29 and Tuesday 30 September.

Unison North West regional organiser James Bull said: ‘Ambulance bosses need to stop stalling and start talking.

‘Staff have already taken weeks of action fighting for the reinstatement of a vital payment that's been taken from them.

‘It's no wonder the ambulance service has a recruitment and retention crisis when managers ignore calls from workers and the public to even talk to their staff.

‘These are highly skilled professionals who provide vital training and support to ensure ambulance call centres are ready to react whenever lives are at risk.'

The latest walkouts follow 22 days of strike action earlier this year in an escalating row about the removal of a payment worth up to £3,000.

An North West Ambulance Service spokesperson said: ‘The dispute relates to a restructuring of a small group of training staff.  The team restructuring significantly expanded the pool of people who could apply for the post, and as a result, an additional payment designed to attract and retain staff was no longer required. The changes were consulted with staff and trade unions and are in line with national terms and conditions.

‘Existing staff were protected, so they did not suffer a detriment, which means no staff had any pay removed. The newly appointed staff knew the posts no longer attracted a recruitment and retention premium when they applied for and accepted the positions.

‘The action has not affected our ability to respond to patients or the wider healthcare system or cover planned training sessions.'