Chelsea have issued a High Court claim for £16million against FC Lyn Oslo and Morgan Andersen over the transfer of John Mikel Obi.
The Barclays Premier League club want the £16million fee repaid as they believe the transfer was based on the fraudulent misrepresentation the player had an employment contract with Lyn.
The claim is being made against both the club and Andersen following the former chief executive officer's criminal conviction in Norway.
A statement from Chelsea confirmed: "Chelsea Football Club has issued a claim at the High Court in relation to the transfer of John Mikel Obi in June 2006.
"The claim is against FC Lyn Oslo and Morgan Andersen and follows the criminal conviction in Norway of Lyn's former chief executive officer Morgan Andersen.
"It is for the entire £16million fee paid by Chelsea for the player as it is now clear following Andersen's conviction that the transfer was based on the fraudulent misrepresentation that Obi had an employment contract with Lyn.
"At the time of the transfer, Chelsea, Lyn and Manchester United agreed that the fees paid would be in final settlement of the transfer, any claims related to it and that no further action or comment regarding the transfer would be made.
"Chelsea has written to Lyn to make clear that because the transfer was based on a fraudulent misrepresentation, now proven by a court of law, the settlement previously agreed is not binding.
"Chelsea is in contact with Lyn and looks forward to working positively with them to resolve the claim promptly.
"Chelsea would like to make clear that this legal action is against Lyn and Morgan Andersen."
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