But the Parkhead club are adamant they will do everything they can to prevent O’Neill, who has guided them to two successive Premier League titles, leaving Glasgow.

A Celtic spokesman said: ‘‘It is safe to say if Leeds or any team approached us, the club would do everything in its power to keep Martin at Celtic.’’

Celtic players jetted off to Ireland this morning for two pre-season games in Dublin - but O’Neill was not on the plane with them.

The Celtic boss is understood to be already in Ireland in a move that prevented him answering more questions over his future yet only added to the speculation.

O’Neill is understood to be the man Leeds want to succeed O’Leary who was sacked more than a week ago, although so far there has been no confirmation of any official approach for the Celtic manager who has 11 months left on his contract.

O’Neill’s decision to take an earlier flight has already been interpreted in different ways by the media.

Some believe it is an indication that he is about to tender his resignation to major shareholder, Dermot Desmond, who lives in Ireland. Others feel he is about to put pen to paper on a long-term contract extension agreement.

Because of the media circus surrounding Celtic the games with Shelbourne and Shamrock Rovers on the Saturday and Sunday respectively have largely been ignored.

Captain Paul Lambert insisted he and his fellow players were not too worried about the intensity of the speculation surrounding their manager, which briefly included Leeds’ own Clubcall service declaring the Celtic manager would be their boss within seven days, a bold claim the Yorkshire club has since officially quashed.

Lambert said: ‘‘‘I won’t believe anything until I hear it from Martin himself. It doesn’t really affect me. As far as I am concerned he is still the manager.’’