He cleared his desk on Friday in a move described by the company as a decision to move on. It is understood that he felt he had taken the paper as far as he could.

An insider revealed that staff were shocked and upset by the news and at losing a capable and experienced journalist.

There was no official comment tonight, with managing director Graham Ayres expected to release a statement on Monday.

The paper has won several awards under Murray's tenure including Newspaper of the Year and Community Campaign of the Year at the EDF Energy East of England Media Awards 2006, Scoop of the Year at last week's Newspaper Society awards, for Meet City's Sex-Change Mayor and Mayoress, as well as Front Page of the Year and Campaign of the Year at this year's internal company awards.

A range of editorial initiatives were put in place, including the introduction of "Sunrise" editions to capture a new audience.

Like most regional dailies, circulation has been falling - around 2,000 to 25,720 in the past year, which is -7.6 per cent.

The newspaper has no deputy, with Murray's former No2 James Foster leaving to edit the Norwich Evening News last August. Assistant editor John Deex is the senior editorial executive and is expected to run the newsroom for the forseeable future.

Murray told holdthefrontpage on Friday lunchtime that he was still working at the paper and was surprised to be fielding a call.

He joined the paper as editor in November 2004, taking over from Colin Grant, who had been in charge for six years.

Murray's previous role was deputy editor of the Chronicle, Newcastle.

He has wide experience of newspapers and has previously worked as news editor at the Belfast Telegraph, the Edinburgh Evening News and the Daily Record, and assistant editor at the South Wales Argus and The Sun.

He began his career in journalism at the Worthing Gazette, before moving to the Southern Daily Echo when he became a qualified senior. He was there for seven years, and took in roles including political editor, chief reporter, assistant and then deputy news editor.

He moved to television as deputy news editor for the then TVS company, working on new shows fronted by Fred Dineage and Fern Britton.

He returned to the regional press after working at the Daily Record.