Liverpool have confirmed their signing of Birmingham winger Jermaine Pennant on a four-year deal reputed to have cost them £6.7m (€9.8m).

Originally Liverpool tried to sign the player for £3.5m (€5.1m), but they have been forced to almost double that because Birmingham have to pay 25% of any fee to his former club Arsenal under the terms of the deal that took him from Highbury to St Andrews for £3m (€4.4m) a year ago.