Thousands of UK post office workers who are members of the Communication Workers Union (CWU), are walking out in strike action for 24 hours in a row over a pay and conditions dispute in the Royal Mail.

CWU official Andy Furey said the union had to call a strike because its legal mandate for taking action was about to expire.

"It's really a ridiculous aspect of the law,” Furey said. “It had not been our intention to call further strikes, but the attitude of the employer, in the context of our need to comply with statutory legislation, left us with no choice.

"We are confident that the strike, the sixth strike of CWU Post Office members, will be as solidly supported as each of the previous actions,” Furey added. "And unless there is a serious pay offer, with increased money on offer, then not only will this action go ahead, but we will also begin the process of undertaking a second national strike ballot."

The CWU said the Post Office had increased the pay offer for 2022/23 from an initial 2% with a £250 cash lump sum to 5% with a £500 cash lump sum. But it said this was still "some considerable way behind" current inflation levels.

A Post Office spokesperson said, “We want to assure our customers that the vast majority of our 11,500 branches are unaffected by the CWU decision to strike and will be open throughout the day.”

“There are 114 branches, typically in city centres, that are directly managed by Post Office and on previous strike days over half have opened as usual,” the spokesperson said. “We’re disappointed that the CWU have made the decision to strike but remain hopeful that we can reach a pay agreement soon.”

In July a controversial new law came into effect that aims to allow businesses impacted by industrial action to plug staffing gaps with agency workers. Earlier this month, UK trade unions, coordinated by the Trades Union Congress and represented by Thompsons Solicitors LLP, launched legal proceedings to protect the right to strike.