On 19 August 2005, midfielder Michael Essien moved from Lyon to Chelsea. The £26 million transfer fee made him the Blues' record signing at the time and ended a three-month battle between the two clubs for the player's services.
Chelsea first expressed interest in Essien in May 2005, the year Essien was named the Ligue 1 Player of the Year. They offered £10 million, but were promptly rebuffed by Lyon president Jean-Michel Aulas. In June, Aulas rejected a proposed swap deal involving recent Chelsea signee (and then-record transfer fee holder) Didier Drogba, joking that he'd be interested only if Chelsea had signed Samuel Eto'o or Adriano. By the end of June, Lyon rejected Chelsea's renewed bid of £16.75 million.
By July, Essien publicly stated that he wanted to make the move, saying "I have made my choice. I want to go to Chelsea." In response, Lyon set a £31 million price tag on him, plus a demand for a player in exchange. When Chelsea failed to pay by the beginning of August, Aulas hinted that Manchester United were also interested in Essien. A few days later, Lyon rejected an improved Chelsea offer of £21 million, plus Portuguese midfielder Thiago Mendes.
By 12 August, it was clear that Lyon could not persuade Essien to stay. The club announced that he would sign with Chelsea for a £26 million fee - £2 million more than the London club had paid to acquire Drogba from Marseille. Essien's record did not last long, however, as less than one year later, they purchased striker Andriy Shevchenko from AC Milan for £30.8 million.
Chelsea's current record for most expensive signing was set by the acquisition of striker Fernando Torres from Liverpool in 2011 for £50 million.