The Catholic Church and local authorities have been criticised after trying to claim child sex abuse victims "consented" in a bid to avoid compensation payouts.

Lawyers who represent some of the victims have told the Sunday Telegraph that the defence is more frequently being used by private schools, religious groups and local authorities when trying to defend compensation claims.

The revelation comes after news that the Criminal Injuries Compensation Scheme, a Government agency, was denying some children compensation because it said they had "consented" to abuse - even if they were of an age where they could not do so legally.

Siobhán Crawford, of London-based firm Bolt Burdon Kemp, one of the largest firms in the field, said the defence is normally used where a child turns 16 during the abuse.

She said the firm had dealt with ten such cases, and there had been an increase in the past two years as authorities became aware that it was an option.

For adults in a position of authority, it is illegal to have sex with a child under their care, even if the child is 16 or 17 at the time.

Anne Longfield, the Children’s Commissioner for England, said: “No child ever gives their ‘consent’ to being abused, and the increased use of this line of defence, although still quite rare, is worrying.

"I have contacted the Ministry of Justice previously and again recently about this issue and the Government should look urgently at what can be done to tackle it.”

The Sunday Telegraph has seen documents for two cases where the defence was employed.

One claimant was told by lawyers for the Catholic Archdiocese of Southwark that his abuse, which included rape and began when he was 15, "actually occurred in the context of a consensual relationship (albeit one the Claimant in retrospect now appears to regret)".

The victim, who cannot be named for legal reasons, told this newspaper that the use of the defence felt "insulting". "I was below the legal age of consent anyway and there's a grooming element to that kind of situation. It was totally disregarded and it made me feel really small," he said.

The case was eventually settled for £80,000.

In another case, a pupil was making a claim following sexual abuse by her teacher. The abuse began when she was under 16 and continued into adulthood.

The local authority, Cambridgeshire County Council, claimed in defence documents that it was not liable for abuse which took place after the age of 16.

It said: "On her own account the Claimant voluntarily sought out contact with [the teacher] and considered that she was in a relationship with him. If that is correct, after she had obtained the age of 16, the Claimant consented to sexual acts with [the teacher] and those acts ceased to be assaults."

The pupil eventually received £550,000 in compensation from the authority.

In a statement a spokesman for the Archdiocese of Southwark said that "out of respect for each claimant’s privacy and the confidentiality of the legal process, the Archdiocese does not comment on individual case", but added that it "supports the right of anyone who has suffered harm to seek compensation. Such claims are complex and often involve a number of difficult legal issues."

A Cambridgeshire County Council spokesman said the abuse was "deeply regrettable" and added: "We would like to say once again, how sorry we are to the woman involved in this case.

"We have already faced up to our responsibilities for this historic case and made a full compensation payment of £550,000 without putting the victim through the additional trauma of a court case.”