Government introduced new guidelines in 2013 to help young victims

NSPCC: Some cases collapse when victims do not have enough support

But only 989 of the cases, which include rapes, led to criminal charges

Figures show Met Police told of 7,205 serious sex attacks on under-16s

Fewer than one in seven child sex abuse cases probed by Britain's largest police force have led to criminal charges, figures have revealed.

Scotland Yard investigated 7,205 reports of serious attacks on under-16s between 2010 and October last year - just 989 of which (14 per cent) ended with a person being prosecuted.

Fewer offenders still were convicted after prosecutors, who were handed details by London's Metropolitan Police, tested cases against them through the courts.

Failed: One in seven child sex abuse claims in London end in prosecution, figures show (posed by model)

The figures, obtained by Mike Sullivan for the Sun on Sunday, show police success rates lagging despite a major crackdown on child sex abuse.

The Met reportedly brought in up to 100 extra officers in 2013 to tackle sex abuse cases including child exploitation and the threat of grooming gangs.

The shake-up was an attempt to improve the Met's controversial Operation Sapphire rape unit after it was accused of failings in previous years.

An IPCC report in 2013 found 'under-performing and over-stretched' officers in Southwark, south London, had encourage adult victims to retract their allegations to boost detection rates.

Today's figures are said to include rape, gang rape, child trafficking and sexual assault.

Changes: The Met Police reportedly brought in up to 100 extra officers in 2013 to tackle sex abuse cases

Last year the NSPCC warned child rape rates were even worse than official figures suggest because many cases are never reported to the authorities.

'Not all cases come to the attention of the police and, even if they do, they may decide it is not in the best interests of the child to investigate an incident as a criminal offence,' a spokesman said.

The charity previously said some child sex abuse cases were collapsing because children were being denied the support they needed to give evidence in court.

Claiming fewer than a quarter of 23,000 offences in 2012 ended in a prosecution, the charity said all children giving evidence should have an intermediary to help deal with 'hostile' questioning.

Responding to the call, the government issued new guidelines saying child sex abuse cases should only be dealt with by specialist prosecutors who ignore 'myths, stereotypes and prejudices'.

Victims must also be offered 'appropriate support' such as counselling and criminal cases should be heard in court with as few delays as possible, the guidelines added.

The Metropolitan Police did not immediately return requests for comment on today's figures.