Spanish defender Carlos Cuellar is set to become Martin O'Neill's sixth summer signing after current club Rangers agreed to the transfer of their star man to Aston Villa in a deal said to be worth around £7.8 million.

The Spaniard - the Scottish Football Writer's Player of the Year for last season - is set to have a medical at Villa's Bodymoor Heath training ground on Tuesday after talks between Villa and Gers late Monday.

A statement on the Rangers website late last night confirmed Cuellar and his agent had informed the Scottish Premier League side on Sunday of his desire to invoke an exit clause in his contract for 10 million euros (around £7.8 million) and an offer had now been agreed for that amount and received from Aston Villa.

The statement continued: "An offer to extend the player's contract and increase his salary was declined with the player adamant he wants Premier League football."

The news came within hours of confirmation that another Villa defensive target Younes Kaboul had left Tottenham for Portmsouth in a £10 million move.

But Cuellar, an integral part of Rangers' bid to do the "quadruple" and the interest of a £10 million bid from Spurs earlier this summer, himself said: "I came to Rangers due to the professional manner of their officials and the management and their promise of success.

"Everything I had been told about this fantastic club has been true and last year's Uefa Cup is something I will never forget.

"My ambition has always been to play for my national team and I believe that playing in the best league in the world for Aston Villa will help me relaise that.

"When I told Martin Bain (Rangers' Chief Executive) on Sunday that I wanted to leave I did so with great sadness. The Rangers supporters have been very good to me but I am young and I want to play at the highest level.

"I hope they will always welcome me back. I want to thank them for everything."

Manager Walter Smith said he was "extremely disappointed" to lose such an important player. He said: "This has coem as a surprise and I am disappointed.Carlos Cuellar has been a great player for this football club and inevitably there has been speculation about him playing in the Premier League.

"The club has received a substantial uplift in the form of the fee and will now reinvest that in the team."

Speculation was also mounting last night that Aston Villa boss Martin O'Neill is about to smash the club's record transfer with a £15 million bid for Chelsea and England midfielder Joe Cole as it emerged that the club's current star player Gareth Barry may yet play his part in Villa's Uefa Cup second round qualifier in Iceland later this week.

O'Neill last night confirmed England midfielder Barry could be included in the squad which travels to take on FH Hafnarfjordur on Thursday as the manager prepares his team for the game which is the key to European success for Villa this season.

 Cole, 25, would certainly fit in with O'Neill's long term plans for Aston Villa who are desperate to progress in Europe this season and also steal a march on the so-called Big Four clubs of Manchester United, Chelsea, Arsenal Liverpool by attempting to break into the upper echelons of the Barclays Premier League.

 The former West Ham United player is said to be unsettled at Stamford Bridge with the arrival of fellow midfielder Deco and with manager Luiz Felipe Scolari also chasing the services of Robinho.

 It is understood Chelsea may yet be considering a new five year deal for Cole however who was their star man last year but who may yet be tempted to join O'Neill's English revolution should Blues' agree to open talks.

The Gareth Barry saga meanwhile was continuing to rumble on last night although the former Villa skipper's dream move to Liverpool looks to be slipping further and futher from his grasp with the statement released by the club's Rick Parry at the weekend confirming the Reds believe the £18 million player is too expensive.

"Barry-Gate" has threatened to tear Anfield apart with manager Rafa Benitez said to have been left embarrassed by the fact owners Tom Hicks and George Gillett have decided not to back his demands in the transfer market over the Villa star.

Benitez himself last night claimed he was putting the whole incident behind him to concentrate on preparing the players he has got for this week's Champions League qualifer against Standard Leige.

He is bitterly disappointed that the club will not allow him to pursue his number one target Barry but is also realistic enough to realise that he cannot concentrate too much of his efforts on that matter with such a vital game looming on Wednesday night.

If Barry is named in the Villa squad for the Iceland game then his participation in the Uefa Cup would mean he would not be eligible for Champions League football until January even if his dream move finally did come off.

O'Neill said: "Gareth is our player and, though things could change, if he is still our player on Wednesday morning then he has as good a chance of climbing on that bus as anyone."