The Royal Mail "can be successful under public ownership", according to the Deputy General Secretary of the Communication Workers' Union.
Dave Ward dismissed the argument that Royal Mail cannot survive without private investment as "simply not true", before claiming that that the investors who buy shares in Royal Mail would "take far more out than what they put in".
Mr Ward confirmed that the CWU would be balloting their members for strike action.
The Government outlined its controversial plans to privatise the Royal Mail today - a decision which was widely criticised by the unions.
Every time you lick a stamp you are engaging with a service that's been part of the fabric of Britain for centuries, but that is changing.
The Government will seek to push through the sale of the Royal Mail before unions get the chance to stage a potentially disruptive strike.