Members working at employer services in PT Ops in Benton Park View in Newcastle will be on strike from 23 December until 14 February unless HMRC reappoints the three reps, the PCS said.

The strike action was voted for in a ballot in November with hundreds of members of the Public and Commercial Services Union (PCS) voting in favour of industrial action in support of the three sacked union reps.

HMRC confirmed that the strike action will affect two phone helplines specifically targeted at employers and users of the construction industry scheme (CIS), which are serviced by the customer services group in Benton Park.

An HMRC spokesperson said: ‘We have robust plans in place to ensure we continue delivering critical services for our customers during any industrial action.’

The PCS said the reps had been sacked in relation to their trade union activity.

HMRC does not comment on staff employment matters.

Over 200 members in personal tax operations’ employer services will be taking part in the strike action entailing eight weeks of ‘discontinuous’ strike action, which means the employer, in this case HMRC must be notified in advance of the day of action in a particular week.

Members at the branch are demanding ‘the reinstatement of their reps who have provided them with help and support over the years, and are now taking action to repay that support’, the PCS said.

HMRC warned that phonelines and webchat will be open as usual but callers may experience longer wait times than usual.

There will be notices on the HMRC gov.uk website and through a recorded message advising that delays may be possible.

It is important to note that HMRC cuts people off automatically after 70 minutes and it does not offer a callback facility, as Myrtle Lloyd, head of customer service at HMRC, told members of the Public Accounts Committee at a hearing in December.

This action will involve around 0.5% of HMRC’s total workforce.

One of the sacked reps, Rachel Farmer said: ‘It’s really amazing to see the members in the branch standing up for me, Joel and Gordon by taking part in this action.

‘We never wanted to be in this situation, we just want to be back at work doing our jobs, but it’s so fantastic to see that the members here value the help and support we and the other reps in the branch have given them over the years.

‘It means so much that they are prepared to stand with us and demand that we’re reinstated and that the victimisation of reps at the branch ends.’