You could have told me he was useless!

There is an argument for saying Sir Alex could have given the impostor a run out - let's face it, he couldn't have done any worse.

But the canny Scot was probably mindful of countryman Graeme Souness' howler while with Southampton.

Souness received a call from a man purporting to be George Weah, who advised him to take a look at his cousin, Ali Dia.

In fact the caller was Dia's agent, but he managed to convince the Saints boss to take the player on a month's contract.

Unfortunately for Souness, Dia was only exposed as a fraud when he came on as a substitute in a Premiership match against Leeds and made a complete fool of himself in front of several thousand people.

Needless to say, he hasn't been heard of since.

Then there was the over-exuberant - and probably over the limit - Leeds fan who thought he could do a better job than Peter Lorimer.

Fame

The incident happened during a clash with old rivals Manchester United in the seventies.

Lorimer was just shaping up to shoot, when the fan charged onto the pitch, tackled him and had a go himself.

Although the shot never troubled the keeper, the mystery supporter was enjoying his 15 seconds of fame and ran towards the rest of the crowd with his arms aloft.

Lorimer, naturally, failed to see the funny side, and helped the man off the field with a less than gentle 'reminder'.

It's not often these impostors cause any real harm, though. More often than not, they are simply content to see their picture in the paper or get their face on TV.

There was the guy who got in on the act at Manchester City's promotion party a couple of years ago and the chap who became more of an institution at FA Cup finals than the cup itself.

Would you try to take the ball from this man?

But you have to go to the sport of kings to find the champion hoaxer.

This is the bloke who for years has had his face beamed around the world on Grand National day at Aintree.

Every year, without fail, he will pop up from nowhere as the jockeys walk out to their horses and stroll alongside them, not forgetting a cheeky wave to the camera as he does so.

He clearly takes his inspiration from the London resident who used to turn up in the winning enclosure on the big day with the owner and trainer of the winning horse.

He became such a character that he was interviewed by the BBC. If he was around now, he'd probably have his own chat show.

This should serve as a warning to Manchester United's overpaid superstars, who have already been heavily criticised by skipper Roy Keane.

If they continue to turn in below-par performances in Europe they just might be replaced by wacky individuals desperate to take on the roles of great entertainers.

Now that would be real Roy of the Rovers stuff.