According to the Public and Commercial Services (PCS) union, about 380 members are taking part in the action although the TRP disputes this, suggesting a figure closer to 200.

The TPR says it believes only about one fifth of its staff have been striking and numbers have not gone up in the most recent industrial action.

The TPR employs about 980 staff.

This latest wave of strikes, mainly at TPR's Brighton office, began in January with 10 days of strikes planned this month.

Despite the action there appears to be little progress in the eight month dispute, with the TPR stating that it has exhausted last year’s pay talks but will discuss this year’s pay award and says it is always open to discussions.

PCS general secretary Fran Heathcote has written to Nausicaa Delfas to request a meeting.

Ms Heathcote has said previously that the PCS proposals are reasonable but the TPR will not discuss them. They have accused TPR CEO Nausicaa Delfas of a “head in the sand” attitude.

According to the union, PCS members have only been offered a 3% pay rise on average while other Civil Service employees have been awarded a 4.5% pay rise.

• Editor's Note: Story updated 07.03.24 to add additional information from the TPR.