The former England defender signed a five-year deal at Meadow Lane in the summer after his contract with Portsmouth expired.

But newspaper reports claim the 35-year-old has walked away from his £40,000 a week deal after saying his goodbyes at training on Tuesday.

Campbell's one appearance in a County shirt - at Morecambe on Saturday - failed to inspire his team-mates and Ian McParland's side slipped to a 2-1 defeat.

Campbell's departure comes as the Football League continue their inquiries into the ownership of the club.

The league had requested documentation from the League Two club relating to their major shareholders.

"The Football League is now analysing information given to us by Notts County and making further enquiries," said a Football League spokesman.

"No further comment will be made until after the League's next board meeting on October 8."

Notts County were bought in the summer by a Swiss-based consortium called Munto Finance, fronted by executive chairman Peter Trembling, and then appointed former England manager Sven-Goran Eriksson as director of football.

The identities of the people behind Munto Finance are unknown however, but are thought to include backers from the Middle East.

League rules state that all club directors and significant shareholders must pass a 'fit and proper person' test.

Notts County are therefore obliged to provide details of their owners' identities in order to have the takeover rubber-stamped by the league.

Eurosport / PA Sport