Manchester City defender Kolo Toure says he decided to leave Arsenal because the club failed to strengthen their squad in recent seasons. Toure, who joined City for a reported £16m, said Arsenal's reliance on youth has meant they have lacked leadership. "When you look at Arsenal you see all the great players have left and are now in the past," said the 28-year-old. "Thierry Henry, Patrick Vieira and Ray Parlour have gone. We lost too many leaders at Arsenal." Arsenal went through two captains last season, with Cesc Fabregas replacing William Gallas at the helm after the French defender made disparaging comments about his team-mates. Toure was the last member of Arsenal's 'Invincibles' (the squad which went unbeaten through the entire 2003/04 league season) to leave the Emirates. "Players like Henry, Vieira and Parlour that brought success to Arsenal and I believed it was right at this stage of my career to also move on," he added. "When we were winning the league the spirit was fantastic, we were like a band of brothers." The likes of Robert Pires, Ashley Cole, Gilberto Silva and Sol Campbell - who have all since left the club - were also key members of Arsenal's unbeaten squad. Wenger has recruited promising players like Theo Walcott, Samir Nasri and Aaron Ramsey, while he has also been keen to promote youngsters from the club's ranks into the first team. But he has suggested he could bring the 33-year-old Vieira - Arsenal's captain in the 2003/04 season - back to the club. And Toure suggested that Gunners boss Arsene Wenger's reluctance to match the spending of the other top clubs has led to Arsenal dropping down the pecking order at the elite end of the English game. "The best teams are at the top only because they have the best players and to get those players you have to spend a lot of money," he said. "You can't be successful in football without money. This is the football business." Toure is unlikely to have any such troubles at Eastlands, with City blowing their Premier League rivals out of the water in terms of the transfer fees they have paid so far this summer. With Gareth Barry, Carlos Tevez, Roque Santa Cruz and Emmanuel Adebayor all arriving for big money, City have signalled their intent to challenge the established top four of Manchester United, Liverpool, Chelsea and Arsenal. "City have a project to build a big team and so it is natural it is going to cost money," said Toure. Arsenal finished fourth in the Premier League last season, as well as and have not lifted a trophy since the 2005 FA Cup. Source: BBC