Mail processing centres in Edinburgh and Inverness were closed

The Communication Workers Union (CWU) said a 24-hour walk-out had been well supported, with a high turnout expected for strikes planned at the weekend.

Royal Mail said the "vast majority" of its staff had been working as normal.

Strike action on Friday will affect workers at processing centres as well as delivery staff.

Each section of the company, from the sorting and collection centres to those who make the deliveries, will be involved in 24-hour stoppages over the course of two weeks.

We believe that we have to modernise and change and any strike action plays directly into the hands of our competitors Royal Mail spokesman

Mail processing centres in Edinburgh and Inverness were closed for 24 hours from 1900 BST on Wednesday.

John Brown, the regional secretary of the CWU for Scotland, said there had been 90% to 95% support for the action in the selected offices.

He said far more were expected to take part in the action beginning on Friday.

Staff at mail processing centres in Aberdeen and Glasgow are expected to go out on strike at 1900 BST.

Delivery staff across Scotland are expected to go on strike for the same period.

Shop stewards said Crown Office workers would take action from 1430 BST on Friday, affecting main post offices such as those on St Vincent Street and Bothwell Street in Glasgow.

Increased mechanisation

A spokesman for Royal Mail said: "The issue at the heart of this dispute is change.

"We believe that we have to modernise and change, and any strike action plays directly into the hands of our competitors."

The union said the action reflected its growing frustration with the Royal Mail for its failure to take worker demands for job protection and increased pay "seriously".

The CWU fears 40,000 jobs will go as a result of increased mechanisation of the system.

The union is also objecting to a 2.5% pay offer.