Middlesbrough tonight confirmed they have rejected a transfer request from Stewart Downing, the England winger. The 24-year submitted a written transfer request first thing this morning in the wake of an improved offer from long-time suitors Tottenham.

“We received a written transfer request from Stewart this morning," Keith Lamb, the Middlesbrough chief executive, said. "It was considered before being rejected.

“Prior to receiving the transfer request, we received an improved offer for Stewart from Tottenham. We immediately rejected this offer and informed Tottenham that Stewart Downing is not for sale and any further interest they have in the player will not be entertained.”

Boro’s response comes as no surprise after Lamb, chairman Steve Gibson and manager Gareth Southgate all repeatedly insisted that the Academy graduate is simply not for sale. However, they now face a task to persuade Downing that he can fulfil his potential the Riverside Stadium after his father, also Stewart, revealed his decision to ask for a move was motivated by his disappointment at the club’s lack of ambition since he signed a new five-year deal in February last year.

Downing Snr said: “Stewart’s been frustrated since the summer, really. When he signed his new contract, he was assured that there would be significant investment in the squad.

“He feels that the club haven’t matched those expectations. He’s also frustrated that the team is once again struggling in the Premier League. Obviously as a Middlesbrough lad, he’s thought long and hard about the decision to hand in a transfer request and he also hopes the fans will understand his reasons for doing so.”

Tottenham have been on Downing’s trail for several years and had already had a series of bids turned down, and it remains to be seen whether or not they test Boro’s resolve to hang on to the player - or indeed, their patience - by returning once again with an improved offer.

It is understood Spurs’ latest offer amounts to in excess of £11 million, although the Teessiders value him at closer to £15 million.

Boro are currently 17th in the Barclays Premier League table, clear of the drop zone only on goal difference, and Gibson is adamant none of their big names will be sold this month despite interest from various parties in Downing, Tuncay Sanli and Gary O’Neil, among others.

Southgate freely admits he cannot spend in January unless he sells, but while he knows he could raise a sizeable sum by selling his former team-mate to Spurs, replacing him - even with the promising Adam Johnson at his disposal - would not be easy.

In addition, supporters will hope there is not a repeat of the long-running Ayegbeni Yakubu saga of two summers ago when the unsettled Nigerian was eventually sold to Everton for £11.25 million, but with no time left to plug the gap he left.

O’Neil too is understood to be considering his future after a difficult first season in the north-east, although Boro have rejected suggestions that he too has handed in his own transfer request amid suggestions he could return to Portsmouth.

Lamb said: “We have not received a transfer request from Gary, but if we did receive one it would be rejected, as would any offer from another club. We believe that this squad of players is strong enough to substantially improve our league position and we are committed to keeping the squad together.”