The commentator hopes the recently-snubbed former England international stays at Ibrox for the long-term but is expecting a top clubs in the Premier League to come sniffing around with a bid of more than £20million projected this summer.

Ferguson remains hoping that the clear bond between the 31-year-old and Philippe Clement would see off the transfer threat but if the temptation proves too much he is stunned by the profit that could be on the books.

Speaking exclusively to Ibrox News he said: “To think we got him for nothing, on a free, and we could sell him for, and I’m going to say this, £20m-plus, what a bit of business that would be.

“But you want top players to be at Rangers and you want to win things. He’s got that relationship with the manager, you can actually sense that, the respect between the two of them.“So fingers crossed Big Jack stays with us but I wouldn’t be surprised if one of the big boys down in England wants to come in and take him up.”