Of course these so called big clubs would sign him but I can assure you now he'll never play for another British club. Italy is a no no and Real Madrid is non starter.
Torres is a professional footballer first and a fan second, dont kidd yourself he will play for whoever is the best for himself to win trophies and pay him what he wants and that will be all the biggest clubs United, Madrid, Barca, City and Chelsea. I think it may be to soon for him signing for City as they are still about 2 more seasons away from winning the Premier League and about three for winning the Champions League, but if Madrid have the best team he will sign for them, take no notice about his Athletico connections he left the club he so called loved to better himself as a player and if Madrid can provide that platform to reach all his goals there is no way on earth he will let playing for a rival club stand in his way. Torres is a professional player first and foremost and has had a little taste of success winning the Euro's with Spain and will want more i can assure you of that.