A minister who allowed a registered sex offender to work as a PE teacher will keep his job, Downing Street has said.
Kim Howells was a higher education minister
Kim Howells, who has since moved from education department to the Foreign Office, admitted making the decision to clear Paul Reeve to work in schools.
Mr Howells said he had been told Mr Reeve "did not represent an ongoing threat to children".
Downing Street said the minister had followed correct procedures and would not be sacked.
Mr Howells was also backed by his current boss, Foreign Secretary Jack Straw, who said he thought the minister had "acted properly".
Education Secretary Ruth Kelly had been under pressure to name the minister who made the decision after she admitted a "small number" of sex offenders had been cleared to work in English schools.
Police caution: Given to people admitting minor offences - placed on sex offenders' register but not automatically barred from schools
Conviction: Defendant sentenced in court - goes on sex offenders' register and put automatically on education blacklist, List 99
Meanwhile, it emerged on Friday that a sex offender had been allowed to work as a teacher at schools in South Tyneside and Co Durham from 2003 to 2005.
William Gibson, 59, had been convicted for an indecent assault on a child in 1980.
He was employed as a maths teacher at St Joseph's RC Comprehensive School in Hebburn in 2003 - but the school discovered his convictions after three months and dismissed him.
But in 2004 he found work through a supply agency at Hebburn Comprehensive - and was dismissed after one day's teaching.
He later worked at another school in Co. Durham.
On Thursday, Ms Kelly announced she would be rushing through new laws to tighten up restrictions on sex offenders.
She said she would make a statement to MPs on the number of offenders working in schools "as soon as possible".
In his statement, Mr Howells said: "As duty minister for the Department for Education and Skills in the first days of May 2005, it was my job to reach a decision on any cases put to me under long-standing arrangements followed by government ministers of both parties.
"I read Mr Paul Reeve's file very carefully and sought advice about the facts contained in the file.
"They argued that this person did not represent an ongoing threat to children but that he should be given a grave warning.
"I took that advice in good faith and acted accordingly."
He added it was then up to any would-be employer to decide, "with all of the facts in front of them".
This letter - which reportedly said Mr Reeve was deemed "trustworthy" and would be a "loss to the teaching profession" - enabled Mr Reeve to get a job at a Norwich school.
Mr Reeve was arrested in 2003 by Norfolk Police as part of Operation Ore, the largest inquiry into child pornography undertaken in the UK.
He received a police caution for accessing banned images of children on the internet but he was only stopped from working at the school when police, who had warned he was a risk, alerted the school's headteacher.
Mr Reeve would automatically have been banned from teaching if he had been convicted of a sex offence.
But because he had accepted a caution he was not placed on List 99, the teaching blacklist, and he successfully convinced the education department and the school he was not a risk to children.
On Thursday, Ms Kelly told MPs she wanted to close this loophole by ensuring cautions and convictions were "treated identically", with the "closest possible alignment" between the sex offenders register and List 99.
Shadow education secretary David Willetts said: "I think it's good that Kim Howells has come clean like this and to be honest I think it's a refreshing contrast with the approach we have had from his boss, Ruth Kelly."
Liberal Democrat president Simon Hughes also said more needed to be known about the case and the ministers involved.
"I don't think automatically either should resign. I don't take that knee-jerk view," he said.
He said if Mr Howells had carried out all the procedures under the present law and process and taken advice and given that information to the employer "and they were aware of all the facts - then he behaved properly".
'Daily Mail test'
A former Labour education minister told BBC Radio 4's The World at One that ministers regularly had to decide on other similar cases.
The ex-minister, who did not want to be named, said the department would be given a full briefing on the teacher concerned, often including psychiatric and police reports.
Ministers often applied the "Daily Mail" test - how would this case look if it were splashed over the front of the newspapers, the ex-minister added.
The former minister could not recall ever approving a teacher returning to school in such circumstances.