It seems the law on this has been misinterpreted for 30 years:
http://www.bbc.co.uk/news/uk-35598896
And lots of people may have been wrongly* convicted.
Whilst I'm not entirely comfortable with the law in terms of how it has been used (e.g. the example in the bbc report - one bloke was in the house, so clearly the bloke in the car didn't do the killing), I'm concerned that this will lead to a reduction in the number of crimes leading to a conviction especially where gang behaviour is concerned.
The question is how do you deal with these kind of "combination of offenders" leading to a death for example.
Imagine if you will a bloke gets set upon by a gang of 6 youths, punched and kicked by all of them, and when they leave its obvious one of them has stabbed the victim who has bled to death.
However the police/cps are unable to determine which of the youths stabbed him (but could prove all 6 youths were there and participated in the beating) in this case surely a murder conviction should be made, but who do you charge with Murder and who's just an accessory?