Announcing next week's strike action, Unison bosses in Northampton said Wednesday would see pickets and a rally through the town centre while Thursday would see "a buffet for those activists who have taken part in our industrial action... for activists to come together and share stories and have a drink to celebrate the successful action."

Striking workers could include refuse collectors, street cleaners and classroom assistants.

Robin Palfrey, a Northamptonshire branch secretary of Unison, said: "A lot of people who are on the picket lines will get a lot of intimidation from across the board.

"It is a bite to eat in a local hostelry saying thanks for turning up and putting up with whatever we have put up with."

When asked if it was fair for striking public sector workers to be in a pub while the residents of Northamptonshire suffered disruption to their services, Mr Palfrey said: "That's one way of looking at it."

It is not known yet which services will be most affected by the strike – which will see pickets on both days – but Mr Palfrey said schools would be closed because of the disruption.

Trading standards and the youth offending team will also be part of the action.

Sally Keeble, who is the Labour MP for Northampton North, said: "I think this is totally wrong and I'm very sorry Unison has decided to do it.

"It smacks in the face of other employees who are having genuine difficulties given the current climate, and workers in the private sector who perhaps aren't getting pay rises and might be looking at Unison members and thinking, 'if only'.

"These people are perfectly entitled to vote for industrial action, but if they are seen to use it just to have a knees-up, it is insulting.

"There are vulnerable people in the county who rely on important services from their councils and I hope Unison have ensured emergency cover during the strike."

A spokesman for South Northamptonshire Council said the full impact of the strike would not be known until next week but the authority was working to make sure, as far as possible, that refuse and recycling facilities would be provided.