25 September 2013 Last updated at 05:20 ET
Crown post offices are the biggest branches within the Post Office network
Staff at the UK's 372 Crown post offices are to take part in their 12th round of strike action in a dispute about closures, jobs and pay.
Members of the Communication Workers Union in England, Wales, Northern Ireland and most of Scotland will walk out on Monday.
It will be followed by a strike in some branches in Scotland on Tuesday.
Staff have also been taking other forms of action including a sales ban on financial products and services.
Crown post offices are the biggest branches in larger towns and cities which make up 3% of the entire Post Office network, and handle about a fifth of its customers.
The union is opposed to plans to franchise or close 75 Crown offices.
Source: BBC News - Business http://www.bbc.co.uk/news/business-24240867#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa
