Souness left St James' Park at 1420 GMT on Thursday

The Magpies have won only one point in six Premiership matches and are just six points above the relegation zone.

Souness, 52, took charge of Newcastle in September 2004 after Sir Bobby Robson was sacked.

Souness expressed his disappointment at being forced out. "I'm saddened at the way things have worked out," he said.

"I have enjoyed living and working in Newcastle, and my family and I have been made to feel particularly welcome by the Geordies.

"I wish the club, the players and the supporters good fortune and success going forward," added the Scot who left St James' Park at 1420 GMT after spending the morning at the club.

Sep 2004 - Takes over as manager - HIGH Oct 2004 - Unbeaten after nine games in charge - HIGH Feb/Mar 2005 - Eight straight wins including knocking Chelsea out the FA Cup - HIGH April 2005 - In space of four days they go out of FA Cup and Uefa Cup. Three players are sent off in defeat to Villa - LOW May 2005 - End season in 14th place - LOW July 2005 - Sells Craig Bellamy after long feud - LOW Aug 2005 - Signs Michael Owen for £17m - HIGH Aug 2005 - Go out of Intertoto Cup - LOW Nov 2005 - Knocked out of League Cup by Wigan - LOW Feb 2006 - A 3-0 defeat at Man City brings reign to an end - LOW Feature: What went wrong?

Meanwhile, assistant boss Dean Saunders has been suspended on full pay ahead of a meeting with the club to iron out a settlement.

Souness' 16-month tenure at the Magpies helm was a rollercoaster ride.

With only 36 victories in his 83 matches, the pressure was almost always on him - and the 3-0 defeat by Manchester City on Wednesday proved the final straw.

Magpies fans protested at the match by displaying a 'Souness Out' banner during their side's woeful display at Eastlands.

Yet despite not having the backing of the fans and with his side languishing in 15th place in the Premiership, Souness vowed to stay on.

He insisted: "I am not a quitter and will not quit."

For much of his reign, Souness was hampered by injuries to key personnel - but he also spent over £47m on players.

The biggest arrival was that of England striker Michael Owen for £17m last summer, but he soon became another player on the club's treatment table.

It will now - at least in the immediate future - be up to Roeder, promoted from his position as Academy coach, to try to revive the struggling Tyneside giants.

He will be helped by Magpies' skipper Shearer, who is playing his last season before retiring.

Former England striker Shearer has made no secret of his desire to one day take over as Newcastle boss.