Fifty police officers across the UK have been arrested as part of a crackdown on suspected paedophiles who pay to access child pornography websites, detectives revealed today.

The officers were among 1,300 people arrested on suspicion of accessing or downloading indecent images of children - some as young as five - from US-based Internet sites.

Thirty-five men were arrested in London this morning as part of the investigation - codenamed Operation Ore - following raids on 45 addresses across the capital.

Of the 50 policemen identified, eight have been charged to date and the remainder bailed pending further inquiries. Scotland Yard said none of those arrested today was a policeman.

At a press conference at Scotland Yard today, Jim Gamble, assistant chief constable of the National Crime Squad, said he was not surprised at the number of police officers among the suspects.

"As police officers, we should expect to be held accountable," he said.

"Fifty police officers have been identified and we are not hiding that fact. We want you to know about that to reassure you.

"Police officers are member of the communities that they serve and there will be good people and bad people in the police."

Mr Gamble said the 50 officers were among 1,200 Britons who had been identified as "category one or two" suspects - those who posed the greatest potential risk to children.

In addition, 40 children nationwide - 28 of them in London - had been identified as being at risk of being abused and appropriate steps had been taken with other agencies to ensure that all the youngsters were safe.

Before today's arrests, the Metropolitan Police had executed 75 warrants across the capital with 65 arrests and more than 130 computers seized. Although 7,000 suspected users of "pay-per-view" child pornography sites based in the US were identified in Britain, Mr Gamble said the actual number of offenders would probably be lower, partly due to duplicates.

The Met's Deputy Assistant Commissioner, Carole Howlett, said today's raids represented the single largest operation of its kind mounted so far by the force.

She added: "Our priority so far has been to identify those individuals on the list that pose the greatest threat to children now.

"But this process is on-going ... and it will continue after today, even though it is extremely resource intensive."

Ms Howlett also announced that the Home Office had agreed to allocate an extra £500,000 to support further action as part of Operation Ore.

She said the money would be used to provide extra training in computer forensics for officers across the country and to buy more equipment for analysing computers seized.

Commenting on today's operation, children's charity NSPCC said it had been assisting the Met by responding to any emerging child protection matters.

Colin Turner, head of NSPCC's specialist investigation service, said: "The arrests send out a strong warning to those that think they can remain anonymous and escape the law by using the Internet to trade in child abuse images.

"Behind these indecent, abusive images are real children who will have suffered immense damage and trauma."

Operation Ore is the UK wing of a huge FBI operation which traced 250,000 paedophiles worldwide last year through credit card details used to pay for downloading child porn.

The names of British suspects were passed on by US investigators.

Suspects were traced through the Landslide web site - a gateway to an international collection of child pornography sites.

Thomas Reedy, who ran the web site and earned millions from it, is now serving several life sentences in the US.