Speculation has been mounting over the nature of the technical fault which caused a 15-minute delay in the start of Saturday’s live The X Factor show.

Viewers who tuned in at 8.15 were shown footage of highlights from this year’s auditions – including the first appearance of finalist Johnny Robinson – while ITV claimed a “technical failure at BT Tower” – the building in Central London which relays broadcasting signals – had led to the problems.

And rumours began spreading after the hitch, with fans suggesting that perhaps thieves had stolen copper cable from the BT Tower, fuelling the power failure.

Even politicians began querying the glitch on Twitter, with Shadow Chancellor Ed Balls saying, “Not more metal theft?”

And Harriet Harman – a self-confessed fan of the show – tweeted, “Switched on a few minutes late. What is going on with X Factor? Have scrap robbers stolen all the cables?”

The studio tweeted its own updates to viewers, saying the studio was “ready and raring to go,” but admitting there was a “technical failure”.

Others, however, remain sceptical about the cause. Richard Madeley tweeted that he had “never gone off air ’cause of tech failure” and added, “Live TV is usually fully backed up. We even had a spare generator at C4 in case.”

And Phillip Schofield said, “Now THAT’s got us sitting up and paying attention!”

And the show itself tried to see the funny side of the blackout by referring to Frankie Cocozza’s abrupt departure this week, saying, “No, Frankie Cocozza has not taken the producers hostage.”

A spokesman for ITV told Mail Online that the problem was “outside of ITV and the producers control,” and added, “It was resolved as quickly as possible.”