Peter Lawwell, the Celtic chief executive, came out fighting against his critics yesterday but he has a new crisis to confront with reports that Virgil van Dijk, the Dutch centre half, is keen on a move to England with at least two clubs ready to bid for him.

The Champions League qualifying defeat at the hands of Maribor in midweek was followed by a protest outside Celtic Park by fans, with Lawwell accused of not spending money on players. Yesterday he said there was no "pile of cash" lying unspent and criticised a "spend, spend" strategy as superficial, though he added the Celtic board had a record of backing managers.

He faces a turbulent weekend before the transfer window closes with the news that Van Dijk, the 23-year-old defender bought from Groningen for £2.6m, is eager to move south with Newcastle United and Sunderland among his suitors and prepared to pay upwards of £6m.

Lawwell was blunt in his assessment of the situation, saying: "We do not want him to go. We don't have to sell him."

But sources in England insist Van Dijk wants a move before the window closes on Monday. Lawwell said: "We don't have to go and sell three or four players. We've got a bit of stability there. We don't want to sell him. We don't want to sell our best players. Players might go but we don't want to sell our best players."

He admitted the club had received "phone calls" but said these had been met by "no encouragement".

However, Celtic do seem certain to sign striker Stefan Scepovic, 24, for £2.2m from Sporting Gijon over the weekend. The Serb will undergo a medical today with work-permit issues likely to be resolved. Lawwell, too, dismissed fears that Kris Commons was poised to leave after failing to start either match against Maribor. "His agent is coming in on Tuesday to talk about an extension. We wanted to get the window out of the way first," he said of the former Scotland internationalist.

Lawwell admitted the demise of Rangers had taken "millions" out of the Scottish game but said Celtic had stuck to a prudent strategy that had made the club known as "one of the best-run in the world".

He conceded he had been "slaughtered" by critics recently but added: "You have to look where it's coming from firstly." He said the "silent majority" of Celtic fans appreciated the reality facing the club.

He added: "In terms of the abuse, I've been a Celtic supporter all my life. The pain hurts, in terms of results. In terms of my family, my brothers, my kids, my wife and cousins who all go to the games are who I feel for. I feel responsible for bringing that on them.

"You either put up with it or you don't. That's the business we are in. It's frenzied, it's hysterical and you either say it comes with the territory or you say adios."

Lawwell insisted he still had an "appetite" for the job. "I have a responsibility to Ronny [Deila, the manager] and I want him to do well. I want to sit here and take the thing on."

He added: "Yes, I've been tempted [by other offers] but I've made the decision to stay here."

He elaborated: "I love the club. This is my club. Anything else would be a job; this is a passion. That would be the difference. And I have a loyalty to Dermot [Desmond, the major shareholder]. I like working for him and for the board. But I'm 55 now and can't do it forever. I can't tell where I'll be in five years . . . you're only as good as your last game."