Steve McClaren yesterday issued an appeal for fans to back Middlesbrough's ambitious plans to attract more top quality players in the summer and compete for trophies next season.

The Boro manager has spent £35m reshaping the squad, but revealed he wants to plunge again for up to three signings in an effort to turn the team into major winners for the first time in the club's history.

"We want to be challenging for a place in Europe or a trophy," he said. "It's going to be a big year for that. But we need the stadium to be full, the support of the fans is absolutely vital."

McClaren's message was delivered as chairman Steve Gibson prepares to write to 37,000 supporters, urging them to buy season tickets.

Boro currently have 22,500 and want to build that to 30,000, the figure reached when the club played in two cup finals with Juninho, Emerson and Fabrizio Ravanelli in the side.

And McClaren added: "Since I arrived, 27 players have gone and 16 have come in. There will be no huge turnover this time, instead we're looking at strengthening up to three areas with quality players."

Boro will splash out again if fans make the Riverside Stadium a season ticket sell-out.

Their response is likely to make its first impact by affecting, one way or the other, the bid to buy midfielder Geremi from Real Madrid.

Chief executive Keith Lamb confirmed: "If we have 30,000 season ticket holders it will give us more spending power.

"There's only so much the club can do with the resources available, now it's up to the fans to say 'we're with you, we understand and support you'.

"If they don't, they'll get the team their support deserves.

"This club belongs to the people of Middlesbrough, it's not a plc, it's not owned by the suits in the City. Every penny we raise is given to the manager to invest in the team.

"When we took over we said we would do our level best to give the people the finest possible team and that is what we're trying to do.

"The chairman has put good people in place. Steve McClaren has spent £35m and transformed the team, it's his team now."

And he added: "We've always said the ingredients you need for success are a good manager, a good team on and off the field and a good chairman.

"In the past we've had one or two, but not all three of those things, now we've got them all."