The House of Lords has delivered a stinging blow to US efforts to crack down on international cartels by ruling that a British executive cannot be extradited to Pennsylvania for alleged price-fixing during the 1990s.

The decision in the long-running case of Ian Norris, the former chief executive of Morgan Crucible, is likely to safeguard dozens of other executives from extradition over long-dormant cartels in industries ranging from chemicals to art auctions.