As of 2011, the rule is 1.3 joules for anything capable of full-auto (approx 370fps on 0.2g bbs), or 2.5joules on anything semi-auto. The 1j limit almost came in, by way of removing specific mention of Airsoft from the Policing and Crime act, but this was fought hard against, and airsoft is still in there specifically now, and recognised as a pastime.