Defence lawyers can no longer argue that a child between the ages of ten and 14 is doli incapax or incapable of committing a crime, the law lords have ruled.

The case involved a 12 year-old boy accused of causing or inciting other boys under 13 to engage in sexual activity contrary to the Sexual Offences Act 2003.

It is understood that the victims were a variety of ages and either friends of the boy or members of families he knew.

Delivering the leading judgment in R v JTB [2009] UKHL 20, Lord Phillips said that the boy admitted the sexual activity in an interview but claimed he did not think what he was doing was wrong.

Lord Phillips said the issue was whether s.34 of the Crime and Disorder Act 1998 abolished the defence of doli incapax entirely for children aged between ten and 14, or whether it abolished only the presumption that the child could rely on the defence.

He said that the government had stated its preference for abolishing both the presumption and the defence in a consultation paper published in 1997, and the measure formed part of the Crime and Disorder Bill.

During its passage through the House of Lords, Lord Goodhart twice moved unsuccessful amendments which would modify rather than abolish the rule for ten to 14 year-olds.

Lord Phillips said the amendments were moved on the premise that the clause, as drafted, would abolish not merely the presumption but the defence of doli incapax.

Dismissing JTB?s appeal, he said: ?Parliament was in no doubt as to the meaning of the clause, in part perhaps because in the consultation paper and the White Paper that preceded the legislation the Home Office had made it quite clear what was meant by abolition of the presumption of doli incapax.?

Lords Carswell, Rodger, Brown and Mance agreed.

Chris Read, partner in Hereford firm Coulson Read Lewis, acted for JTB. He said that two similar cases in the Hereford area had been stayed pending the Lords ruling.

?There?s no wriggle room in this judgement,? he said. ?The problem is that having taken this away from us, they haven?t put anything in its place.?

?If we have to rely on mens rea, we will have to bring in psychiatrists in every case.

?Fitness to plead on mental health grounds is still an avenue open to us, but the ramifications of not being fit are hospital orders and confinement in secure units. Hard cases make bad law.?

However Harry Ireland, Chief Crown Prosecutor for Staffordshire, commented: ?Whilst we had no doubt as to the purpose and intent behind s.34 of the Crime and Disorder Act 1998, namely the abolition of doli incapax in its entirety, it is helpful to everyone who deals with young offenders to have this confirmed by the House of Lords.?