George Clooney wanted a live ER

Others have leapt on to the idea, too. A live remake of On Golden Pond is planned for next year and the US sitcom The Drew Carey Show has now done one edition live.

But there is a risk in doing live drama and it is not that the cast may forget their lines - although bets have been placed that the Coronation Street special will go wrong.

Instead, the risk is that everything could go perfectly and we will not be able to tell the difference.

Live TV drama could become an exciting event for the actors and crew but irrelevant to the audience.

George Clooney admits his reasons for doing live drama are experimental: "Why not try to work in the one arena where no one else is allowed to play?

When I was in the position to do something unusual on television, I tried

George Clooney

"Films can't go live. It might help make TV more interesting and it might give viewers a reason to tune in."

ER certainly got viewers tuning in - the live special got 43 million viewers - but it was not a critical success.

"When we finished the live ER, we were so proud of ourselves," says Clooney.

"We thought we had knocked the ball out of the park." But when the excitement was over and he watched a tape, he changed his mind.

"It just had this cheap look. It looked wrong. It looked like a soap opera."

Part of the problem was technical - normally ER is shot on film but for a live transmission it had to be done with video cameras.

It's a significant enough difference that the show decided to come up with an excuse for the new look: the story had a film crew making a documentary about the Emergency Room.

The original Street cast was used to live drama

"The secondary factors in using a documentary crew as part of the story were also crucial," says producer Carol Flint, who also wrote the episode.

"We had a safety net if a boom [microphone] appeared in the shot, and we had a story reason for going live.

"None of us wanted to use [live as] a gimmick for its own sake."

Coronation Street is always shot on video so there should be no discernible difference in picture quality for the live special.

But the show appears to be planning the episode as an ordinary one of the run rather than concocting a story reason for it being live.

None of us wanted to use a live show as a gimmick for its own sake

ER writer/ producer Carol Flint

Trying to make the Street as close to normal as possible could negate the point of being live and so could be a mistake but it could also be clever.

For George Clooney's second foray into live drama, Fail Safe, ignored the idea of looking for a story excuse and instead went live almost for its own sake.

Fail Safe is a nuclear war story, considered to be the serious version of Dr Strangelove and the original novel was made into a film released just months after the Kubrick comedy.

With Stephen Frears directing, Clooney proposed a remake.

"I don't like the idea of remaking good films," he said at the time. "But if we do it live, it's not remaking the movie."

Fail Safe used live techniques to hark back to the mood as well as the technical constraints of early television.

"We are trying to make this old. We want to do the exact opposite of MTV. We want stillness and silence," said Clooney.

"I want to be able to say, 'When I had the reins, when I was in the position to do something unusual on television, I tried. I gave it a run.'"