hundreds of downtrodden mums and dads will be trawling the county's toy shops this Christmas trying to run to earth the only thing that will make the festive season bearable for their dearly beloved child.

This year it is the Harry Potter Lego sets, featuring the Harry Potter Castle, at a trifling £75 or the Hogwarts Express, which comes in at just £40.

Some may feel these are small prices to pay for peace and quiet but the chances of getting hold of one are dwindling every day this side of Christmas.

The Harry Potter Lego collection is joining that elite group of 'must have' toys like the Buzz Lightyear doll from Toy Story, the Furby and, remember Rubik's Cube?

As well as having high-profile connections with hit movies or TV shows, these have that other indispensable ingredient unavailability.

Steve Hogg, proprietor of Hoggosaurus toy shops with outlets in Devizes, Andover and Yate, said: "Despite the fact that the book has sold millions and everybody was talking about the film for months before it came out, Lego have been completely overwhelmed by the demand for the toys.

"They have completely misjudged it but it is only the second time they have been involved with licensed products after the Star Wars collection they put out last year.

"Although we had the stock early on and put in our orders early, Lego took the decision to cancel everyone's orders and allocate their meagre stock on the basis of ten per cent of the order."

Mr Hogg had just had a delivery as the Gazette spoke to him last week but he was confident they would be gone within days.

He said: "Fortunately, my business is not built on hyped products but on service levels of popular lines like Brio, Lego, Duplo and so on. A lot of people got their fingers burnt on the merchandising that came out in connection with the Star Wars film last year.

"They were too hi-tech. A toy that normally might have sold for £4.99 was £8.50 because it had a chip inside it that made it able to do all kinds of things. Very impressive, but a bit too much for most parents."

Many smaller branches of Woolworths weren't allowed to stock any of the Harry Potter Lego merchandise, but they were not concerned as business was booming in so many other areas.

For a bargain price of £29.99, you can have the Weakest Link electronic game, complete with an Anne Robinson mask for the inquisitor and barked demands in Ms Robinson's hectoring tones to hurry up or stop being stupid.

There are other Harry Potter spin-offs besides those made by Lego, most popular of which is Professor Snape's Potion Class, described as a kind of chemistry set where children can create a series of edible treats for themselves.

Bob the Builder retains his grasp over the pre-school market and Barbie, despite her advancing years, is still queen of the dolls. This year her incarnation as the Nutcracker is selling very well, according to the assistants on the toy floor at Woolworths in Devizes.

Or how about the Miracle Doll at a paltry £49.99? Makers say the texture of this delightful dolly is the closest toy technology has come to human skin.

The robotic pet I-Cybie, at £79.99, contains the technology of much more expensive models and probably has a longer life than 4pm on Christmas afternoon.

However, one thing to be aware of this Christmas is the safety of the toys you buy.

The advice from the British Toy and Hobby Association is Look for the Lion mark.

Keith Lister, safety adviser to the toy industry's trade association, said: "This special symbol has been designed to be easily identifiable for both parents and children, enabling them to ensure that the toys they buy are made to the highest European safety standards.

"Our members represent over 95 per cent of the toys manufactured and supplied in the UK and it is our primary concern to ensure that our toys are safe."

The association offers the following advice this Christmas:

Look for the Lion Mark. This friendly lion's face within a triangle is a symbol of safety and quality and is carried on the packaging of association members' toys, indicating that the toy conforms to standards.

Use reputable toy shops, department stores and familiar retail outlets. Look out for shops displaying the Approved Lion mark Retailer Scheme Logo.

Avoid fly-by-night street traders and fairs where the origin and quality of the toys cannot be guaranteed.

Follow age and safety guidelines on the packaging, ensuring you buy a toy suitable for your children's age and ability.

Do your own tests: is the toy well made? Securely put together? With no sharp edges? Always ask for advice in the shop if you are uncertain.