Jim Reeves, from the Communication Workers' Union, says the argument to close 70 Crown Post Offices is flawed because the business is profitable.
He spoke to ITV News Central outside the Kings Heath branch in Birmingham as staff went of strike this morning.
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Sunshine and showers tomorrow. Breezy and feeling fresher.
Clear and mainly dry overnight. Heavy showers developing during Thursday.
Her family thought that she was staying with friends but she has not returned home.