A series of protests are taking place outside WH Smith stores up and down England and Wales objecting to the planned franchising of "Crown office services" from the Post Office to the high street retail chain.
The Communication and Workers Union (CWU) has organised six demonstrations outside WH Smith stores in London, Slough, Swansea, Shrewsbury, Altrincham and Ashton-under-Lyne.
Protesters will attempt to convince WH Smith customers to boycott the store in support of their arguments that the transferral of Post Office jobs to WH Smith will result in a poorer service for consumers.
Andy Furey, assistant secretary of the CWU, said that today's protests were an attempt to prevent the "desecration of the Post Office network".
"It is outrageous that the Post Office can treat long-serving skilled members of staff in this way," Mr Furey said.
"Collectively thousands of years of experience are being axed and scant provision for new services provided."
Thirty-four existing post offices will be closed under the franchising plans, 27 in the Greater Manchester area and seven in south-west Wales.
The CWU is currently balloting its members on industrial action over the issue, which would see the loss of around 500 jobs in total.