With speculation over Owen's future swirling around St James' Park, Shepherd has demanded a public expression of loyalty from the England striker to the club where he has played just 13 matches since being signed for 17 million pounds two years ago.

But the chances of that happening look slim in light of Shepherd's public criticism of the player's advisors, whom he accused of attempting to "flog Owen from under our feet," and his claim that none of England's Champions League clubs were interested in buying the England striker -- a suggestion which seems unlikely and may be regarded as gratuitously insulting by Owen.

English media on Thursday reported that a clause in Owen's contract which would allow him to leave Newcastle for a cut-price nine million pounds (18 million dollars), and Shepherd clearly believes the details have been leaked by people close to Owen.

"These suggestions will not impress our fans after what has happened in the last couple of years," he fumed.

"This report was a very thinly-disguised attempt to flog Owen from under our feet, sourced very close to the player or those who look after him. The information must have come from there, not from our club."

Shepherd added: "I'm telling Michael he has two choices: he either comes out and tells our fans, who have taken him to their hearts, that he is happy here -- or I tell him that not one of the big four clubs, Manchester United, Chelsea, Arsenal or Liverpool are interested in him. Because that's the case.

"The loyalty this club has shown him over the last two years, when he had injury problems in his first season and had missed virtually all of this season, deserves something in return.

"He has had a really serious injury and no-one, least of all one of the biggest clubs, is likely to take a risk at this stage.

"He has to prove to everyone, himself and Newcastle United included, that he is fully recovered and not about to break down again."

Owen only returned to action this month after damaging his anterior cruciate knee ligament during the first moments of England's 2-2 World Cup draw against Sweden last summer.

He has however declared himself fitter than ever following ten months of rehabilitation work and is planning to return to the national squad for their friendly against Brazil and a key Euro 2008 qualifier in Estonia at the start of June.

Good performances in those matches will inevitably trigger fresh interest in the striker and it is not inconceivable that, contrary to Shepherd's claim, all of the top four clubs could be interested in signing him: Arsenal, Chelsea, Liverpool and Manchester United will all be looking to sign at least one new striker this summer.

Shepherd meanwhile rubbished suggestions that Sven-Goran Eriksson is in the running to become the new Newcastle manager following the resignation of Glenn Roeder.

Former Bolton boss Sam Allardyce is widely expected to get the job, despite a claim from Eriksson's agent Athole Still that 51 percent of Newcastle fans backed the former England boss for the job.

Shepherd said: "Where he gets that figure from, I can't imagine. I think 51 percent of Geordies might like the idea of Sven's girlfriend Nancy Dell'Olio on the Newcastle Quayside."