The Supreme Court held, restoring Gnango's conviction for the murder of Magda Pniewska, that he was guilty of murder notwithstanding the fact that he had not fired the shot which killed Pniewska during the shoot out which led to her death, and that the fatal shot had been fired by his opponent in an attempt to kill him.

The judgment of the Supreme Court has been criticised over the alleged extent to which it was designed to mollify public opinion, and in the context of debates over the nature of the doctrine of joint enterprise.

[13] On 23 June 2008, at the Crown Court at St Albans, Mr Justice Cooke sentenced Gnango to detention for life for the murder of Pniewska, with a minimum term of twenty years, and imposed concurrent sentences of detention for public protection, with a minimum term of twelve years, for the attempted murder of "Bandana man" and a minimum term of five years for possession of a firearm with intent to endanger life.

[16] The court held that "[t]he jury was never asked to confront the question whether the shared common purpose was not only to shoot, but to be shot at".

However, noting that it was a "clear case for a sentence which proclaimed the public abhorrence of the crime being marked by it" and the "very grave" aggravating features of the offending, the court exercised its powers under section 4 of the Criminal Appeal Act 1968 to increase Gnango's sentence for the attempted murder of "Bandana man" to detention for public protection with a minimum term of fifteen years.

By a 6–1 majority, the court allowed the Crown's appeal, answered the certified question in the affirmative, and restored Gnango's conviction for the murder of Pniewska.

"[24] They also held that "there is no common law rule that precludes conviction of a defendant of being party to a crime of which he was the actual or intended victim"[25] and that consequently, under the doctrines of joint enterprise and transferred malice, Gnango was guilty of murder.

[26] Lord Brown of Eaton-under-Heywood concurred, adding that "The general public would be astonished and appalled if in those circumstances the law attached liability for the death only to the gunman who actually fired the fatal shot.

[27] Lord Dyson concurred with the leading judgment and would have restored "the conviction on the basis that the jury must have been satisfied that the respondent aided and abetted the murder of Ms Pniewska by encouraging Bandana Man to shoot at him in the course of the planned shootout".

[32] Sir Richard Buxton, a former Lord Justice of Appeal, argued that "The Supreme Court approached the case with a strong propensity to find grounds for convicting G[nango] of murder."

supported this analysis, suggesting that the prospect of Gnango being prosecuted for his own attempted murder "surely would ... be a farcical spectacle", and that the court's concern for public opinion had led it to make an erroneous decision.

[36] Dr Jonathan Rogers, Senior Lecturer in Laws at University College London, suggests that an uncertain (quite obscure) route to finding the facts homicide renders the conviction unsafe and contrary to Article 6 of the European Convention on Human Rights, and that the decision was motivated by a desire to mollify public opinion.