But, in Britain, its main provisions have been incorporated into the Extradition Act, which came into force in January.

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Mr McKinnon was arrested in 2002 and again in 2005 before an order for his extradition was made in July 2006 under the 2003 Extradition Act.

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Lord Bingham, and one of the Law Lords in the first panel who sided with General Pinochet, considered the retrospectivity argument briefly, and then rejected it because the plain language of Britain's 1989 Extradition Act seems explicitly to rule it out.

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