ITV show Britain's Got Talent breached broadcasting guidelines by featuring a horror magician called Dr Gore, Ofcom ruled today.

The "doctor" began his act by appearing to cut off his hand, then he pretended to remove an organ from an assistant, using a rotary saw.

Hosts Ant and Dec introduced him with the words: "He has the power to make audiences feel sick in seconds."

Judge Simon Cowell likened the performance to "a weird porno movie".

Parents said their children had suffered nightmares after watching the Saturday night show on June 16, and media watchdog Ofcom received 21 complaints.

Dr Gore reached the semi-final, which also featured six-year-old Connie Fisher and eventual winner Paul Potts.

ITV said his act had been carefully reviewed to ensure it did not upset young or impressionable viewers, and described it as "pantomime rather than horror".

But Ofcom said the programme had breached guidelines on protecting children from unsuitable material.

The watchdog ruled: "Both Dr Gore and his assistant were dressed in medical clothing and appeared to use a real rotary saw to 'extract' organs and flesh from their 'victim'.

"Therefore, Dr Gore's act, regardless of efforts to edit it and to inject an element of humour, went beyond audience expectations for peak family viewing at the weekend, particularly given that audience figures suggest that more than one million children were watching."

Ofcom added: "This programme in particular featured a singer who was six years old and a dance troupe solely comprising a number of young children, which would have further enhanced the programme's appeal to children and families alike.

"It therefore would have been the audience's expectation, particularly on a Saturday night when younger children are generally allowed to stay up later, that the programme's content before the watershed would be suitable for them to view, not least because it was a variety programme aiming to find a member of the public who would ultimately perform for the Queen."

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