Former Newcastle striker Alan Shearer has labelled Rafael Benitez's departure from the club a "shambles".

It was announced on Monday that Benitez will leave St James' Park following a failure to reach an agreement with owner Mike Ashley over a new contract, with the Spaniard's existing deal set to end on June 30.

Premier League record goalscorer Shearer expressed his disappointment that Benitez, who guided the Magpies to two mid-table finishes in the Premier League after winning promotion from the Sky Bet Championship in 2017, was allowed to walk away from the club.

"A world-class manager. A manager who performed so well in very difficult circumstances. A manager who understood the fans," Shearer wrote on Twitter.

"Thanks and good luck @rafabenitezweb, you were brilliant for the Toon. #SHAMBLES."

For the thousands of long-suffering fans, Benitez's departure came as no real shock and Ashley, who has so far failed to sell the club despite there being interest, bore the brunt of the blame.

"It's no surprise the depths Mike Ashley sinks to," Mark Jensen, editor of online fanzine The Mag, told Press Association Sport.

"Any club who has a manager doing a good job, you make sure you tie him up on a new deal and give him what he wants long before it reaches this point.

"Obviously, as part of the wider picture at Newcastle, it is a club that is only going to go in one direction while Mike Ashley stays.

"Anyone who wants to try to use the takeover as a reason for not being able to convince Rafa Benitez to stay, it is a big fat red herring.

"Even if there had been no talk of a takeover, it wouldn't have made a difference.

"No one who is credible will agree to work under Mike Ashley now."

Ex-Magpies midfielder Lee Clark and former forward Mick Quinn were among others to voice their displeasure at the decision.

"There will be a huge backlash from the support. There will be a lot of anger. I see a difficult summer ahead," Clark told Sky Sports News.

Quinn labelled the situation "embarrassing".

"Well I feared the worst and it's happening, Rafa leaving @NUFC. They offered him a one-year contract and no assurances. Rafa is a world-class manager, he loved his time at the club and it's another sad and embarrassing day for this big club," he wrote on Twitter.

Some of Newcastle's current players expressed their thanks to Benitez for improving them and the club.

Striker Salomon Rondon, who spent last season on loan at Newcastle, tweeted: "I must say that @rafabenitezweb deserves huge credit for what our team achieved last season, and I'm sure he'll have success in his next job. All the best, gaffer!"

Midfielder Isaac Hayden commented: "Thank you for everything over the last 3 years, you brought me to the club and had the faith in me to develop me as a player and person. It won't be forgotten. All the best for the future! @rafabenitezweb #NUFC."

The most damning criticism came from the club's two most famous celebrity fans, Ant McPartlin and Declan Donelly.

"Disastrous. Those 'at the top' of our great club should be ashamed. The great shame is that they won't be," was posted by Ant and Dec's official Twitter account.

"The way they are repeatedly able to snatch defeat from the jaws of victory is astonishing. Thank you @rafabenitezweb. Mike Ashley – get out of OUR club"