Members of the Communication Workers Union (CWU) from Milton Keynes marched through the centre of Bletchley on Saturday.

They claim plans to handle Milton Keynes' post in a new £70 million sorting office in Northampton will lead to the loss of about 600 jobs.

Former Northampton Borough Council member and CWU regional secretary for the Midlands, Lee Barron, took part in the march.

He said: "The workers in Milton Keynes want to retain their own Milton Keynes work.

"They accept some of their current work will go to Northampton, but if a letter is posted in Milton Keynes, they want it to be sorted in Milton Keynes."

The union has said transporting post from Milton Keynes to Northampton and then potentially back to Milton Keynes would add an unnecessary delay to the mail.

But Mr Barron insisted the union was in no way against Northampton getting a new mail centre.

He said: "The people in Northampton want a new mail centre because theirs burned down, but we never asked for it at the expense of services and jobs in Milton Keynes."

Plans for the Northampton depot were approved by the West Northamptonshire Development Corporation in September.

The £70 million centre will be built by Royal Mail in Tithe Barn Way on the Swan Valley industrial estate, close to junction 15a of the M1. It will employ up to 1,000 people and stand on 44 acres.

The new building will replace the Barrack Road sorting office which caught fire in 2003 as well as the Milton Keynes office and another in Coventry.

Royal Mail announced last week the new Northampton depot would be open for 2010.