Post Office workers are set to stage a 24-hour strike in a dispute over pay.
On Thursday, disruption is expected across 11,500 sub-post offices across the UK.
Clerical and administrative workers will walk out in a demand for bosses to take action.
Picket lines will be in place at Springburn in Glasgow and in Aberdeen.
It will be the second strike at the Post Office held this week by workers.
Around 1,500 staff took part in industrial action on Monday, with only half of directly managed branches being able to open.
A current 3% pay offer, alongside a one-off payment of £500, has been rejected by the union for Post Office workers.
The Communications Workers Union (CWU) has called for senior management to “get real” on pay negotiations.
They have warned that the proposals currently on the table are far below RPI inflation of 11.7%.
Members of the union voted by 97.3% in favour of taking action in a ballot earlier this year.
CWU assistant secretary Andy Furey insisted that there is money available for workers.
“The blame for this disruption lies entirely with the senior Post Office leadership, who have repeatedly failed – and wilfully refused – to set out a sensible and fair pay agreement, or engage in meaningful negotiations,” he said.
“Everyone knows that the only solution is a fair pay rise that properly rewards members for their extraordinary efforts in serving the public and delivering a profitable Post Office, while also taking account of the extreme cost of living.
“There is money available, but management do not want to give workers their fair share.”
He added: “Post Office workers are telling bosses loud and clear: don’t waste our time, sit up and get real on pay.
“Until you do this, the strikes will continue.”
A Post Office spokesperson said: “We have a range of contingency measures in place to minimise the impact of CWU strike action in our supply chain today.
“Our 11,500 branches are open as usual. We’re disappointed that the CWU have made the decision to strike but remain hopeful that we can reach a pay agreement soon.”