Blue Peter has admitted another fakery scandal after confirming that two young “viewers” who appeared on the show were really child actors.

Children were asked to apply via the BBC website to quiz Jon Culshaw, the Dead Ringers star, in the television studio. Of the six who appeared on the programme, two were supplied by a local drama group.

The new incidence of fakery - which occurred in September 2005 - failed to come to light during an internal BBC probe ordered by Mark Thompson, the Director-General, earlier this year.

A 13-year-old boy who appeared on the BBC One show uncovered the deception after chatting to the other children. “Two of them said ‘We’re from an agency and we’ve not thought of a question yet’,” he told The Sun.

A BBC spokesman confirmed the incident and said children from the drama group were brought in “to ensure a good range of questions”.

The spokesman said: “Blue Peter organised a light-hearted item in which children got to meet Jon Culshaw and ask him questions which he would answer with an impersonation.

“Of the six children who appeared, four had contacted the programme through the website and two were invited to join them from a drama group.

“The children were all asked to prepare their own questions. None of the children was paid, the item in question was not a competition and no prizes were offered or awarded.

“It would have been preferable not to have given viewers the impression that all the children in the item had contacted the programme through the website.

The BBC spokesman added: "The children were not from an agency, they were from a drama group." He said the programme would continue to use children from drama schools in items but not at the exclusion of other viewers.

“In recent months we’ve taken a number of measures to ensure we get these things completely right, including the introduction of special training, so that viewers can continue to have complete confidence in the programme.”

The episode follows two other instances of viewer deception involving Blue Peter. The results of a competition to name the show’s cat was changed. And a girl visiting the studio was made to pose as a competition winner.

All three instances occurred when editor Richard Marson was at the helm. He has since left the BBC. A source said: “This latest episode happened when Richard Marson was on the programme. He has since been moved off the show and the programme has a new editor.”

Blue Peter has had its airtime reduced and could be moved from its 5pm teatime slot under changes to the BBC One schedule when the channel loses Neighbours.

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