The Communications Workers Union has voted overwhelmingly to support strike action.

Over nine out 10 members of the postal workers union backed industrial action.

Three thousand trade unionists involved in cash handling at post offices oppose Royal Mail plans to privatise their jobs.

The CWU members, who process and deliver cash to the UK's network of 17,500 post office outlets, have rejected the terms for a proposed sale of their division to Securicor.

But this deal now looks likely to fall through as Securicor considers backing out.

CWU chief Billy Hayes hailed the vote as "as clear a mandate as anyone could receive".

"We will go ahead with organisation of strike action within the next few weeks," he said.

"Because of the seriousness of the situation, we are also considering a wider ballot of all our members in the postal industry".

The Department of Trade and Industry recently referred the proposed sale to the Competition Commission.

Concerns were raised that the transfer would reduce the number of cash handling firms in the country from three to two.

The CWU objection is that the proposal does not guarantee the same pension rights and job security their members receive in the public sector.

"Our members would have to accept that their livelihoods are put on the line because of a business decision which we consider to be essentially wrong," Hayes said.

"It is no way to treat employees who put themselves on the line every day carrying out an essential service for the community".

Hayes added that a final decision on how the dispute will be conducted will be made at a meeting of the union's postal executive next Tuesday.

Strike action could mean that post offices are starved of cash and will be unable to provide a service.

A spokesperson for the post office told ePolitix.com that talk of strike action was "premature and foolish".

"The CWU knows our cash position is falling and that we need to make changes," she said.

"We've said all along that we will only talk to buyers who are prepared to offer our staff similar conditions to those they already work under".

She said the post office will continue to look at all options for raising money and is still talking to Securicor about a possible sale.