Staff in Crown post offices in Cornwall are set to join strike action today in a dispute over closures, jobs, and pay.

The full day strike of 4,000 staff, will see Camborne, Truro, Penzance, Newquay and St Austell Crown post offices affected, says the Communication Workers Union.

The strike has been timed for the last Monday of the month to cause maximum disruption.

Dave Ward, CWU deputy general secretary, said: "It's becoming ever clearer that the Post Office is obsessed with cost cutting, closing Post Offices and slashing jobs and local services. This is being done against the wishes of customers and communities and with no political mandate.

"It is a shocking robbery of local services and misuse of public money - with £15.4 million paid out in bonuses to senior managers while front-line staff face job losses and pay freezes.

"Our members' determination has been unwavering because they know they are right; they are standing up to protect jobs, services and for a fair pay rise. The company is in disarray and clearly out of touch with both its staff and customers. We remain firmly convinced that a positive solution can be reached to protect jobs and services, but that will require the company - and perhaps government - engaging in serious negotiations."

The union says that the Post Office wants to close and/or franchise 75 Crown offices, 20 per cent of the network, and cut up to 1,500 jobs.

Adding that while these main offices comprise three per cent of total post offices, they handle 20 per cent of all customers and 40 per cent of all financial services sales, making them the "powerhouse of the network".

It adds that staff at Crown Post Offices have not had a pay rise since April 2011, while all other staff represented by CWU in the Post Office have had two pay rises totalling 6.75% in this period while head office managers shared a bonus pot of £15.4 million.

 Post Office staff voted by nine to one (88 per cent) in favour of strike action and have already taken strike action on eight previous occasions: Easter Saturday, 19 and 29 April, 7 and 28 May, 20 June and 29 June, and 17 July.

Camborne, Truro, Penzance, Newquay and St Austell post office are all on the list of 373 that will be affected.

The state owned Post Office, which is seperate from the soon to be privatised Royal Mail, is state-owned and receives £1.3bn of taxpayer subsidy..

Kevin Gilliland, the Post Office's sales director, said the crown network of the biggest post offices across the country is "losing £40m a year of public money" and "must change the way they operate to ensure long-term viability".