Looking at all the TV-tie-in merchandise that is currently being produced, Doctor Who sticks out like a sore thumb. It is the only show with new merchandise being produced, and current lines of merchandise continuing that is not actually being made. All the others - mainly X-Files, Babylon 5 and numerous variations of Star Trek - are currently in production or are regularly on our TV screens. Other ranges of books based on popular TV shows have fizzled out: there were novels based on Quantum Leap, The Avengers, The Man From UNCLE and The New Tomorrow People but these stopped once the respective shows stopped and the books based on the Bugs series just bombed. Perhaps the closest to Doctor Who is Red Dwarf which enjoys an irregular and widely spaced series of novels, nothing like the two-a-month schedule of Doctor Who.

Then there are the exhibitions. Doctor Who fans have long been spoilt with being able to actually see in person, so to speak, the characters, costumes and monsters from the show. Since the permanent exhibitions were established at Longleat House and on Blackpool's Golden Mile in the seventies, fans have flocked to see the displays year after year. This is something that again seems to be unique to Doctor Who. There is no permanent display of Star Trek material, as far as I know, and nothing on any of the many other cult television shows of the past. Prisoner fans can go to Portmerion, of course, but where do fans of The Avengers go? The Doctor Who exhibition at Blackpool is long gone, but the smaller Longleat display is still going strong. After a couple of temporary sites at London's short lived Space Adventure in Tooley Street, and at the Museum of the Moving Image, Doctor Who has found itself a new and more permanent site at the Llangollen premises of the toy manufacturer Dapol.

This exhibition opened a couple of years ago, but I had never managed to arrange to get up there to see it - for those not familiar with Britain, Llangollen is in Wales, some 200 miles from where I live in London. However, I have just rectified this with a short holiday in the area.

Dapol's exhibition is most probably the best Doctor Who display I have yet seen. It's certainly the biggest, with around 30 'cases' containing in excess of 60 different costumes and props. There are, in fact, far more than this as all the cases, as well as containing the main costumes, are littered with smaller items. As with most of the displays of Doctor Who props over the years, there are a mixture of themed cases, containing, for example, a large selection of Time Lord costumes, and also scenic cases in which the costumes and props are arranged to re-create a scene from the show (like the Cybermen gathered around their Cyberscope device from Earthshock).

What is impressive is the layout and the sheer number of items featured. There are three galleries through which visitors trace a winding path - all the actual props and costumes are behind glass but many have illuminated press-buttons which will make the creatures within light up or sway alarmingly from side to side. In addition, the walkways that link the main galleries have display cases along them that feature different aspects of the show. There are displays for the Doctor Who Magazine, for the Doctor Who Appreciation Society, for Costume design (a great selection of original designs from Ken Trew and others showing how costumes were originally envisaged together with photographs showing how they ended up), scripts and other assorted guns, heads and other unidentified pieces from the show.

As well as the Doctor Who exhibit, as this is Dapol's factory, visitors have the opportunity to see some Doctor Who toys being made. Dapol specialises in small jointed plastic figures from the series, and you can follow the process of their creation through from the initial ideas, to the mould (which apparently costs anything between 30 and 50 thousand pounds!) to the painting, and finally the assembly. It's interesting to follow the process through and certainly gives you some idea of the costs involved in developing a new toy, whether it be Doctor Who or otherwise.

By coincidence, David Boyle, the MD of Dapol, is on the verge of opening two new exhibitions on Blackpool's Golden Mile. One is to concentrate on Red Dwarf - apparently all the props and spaceships from all the series still exist - while the other features extraterrestrial visitors from beyond - little grey men, Roswell, government conspiracies and the like. If they're as well put together as the Doctor Who one, then he's onto another winner.

While I was up in the area (actually staying just outside Shrewsbury) I took the opportunity to drag the wife and kids off to Ironbridge Gorge. Apart from the fact that there is loads to do there, it's also where Doctor Who went on location for the Colin Baker story, The Mark of the Rani.

Apart from being one of the most incomprehensible Doctor Who stories, The Mark of the Rani featured one of the best locations, that of the Blists Hill Open Air Museum in Ironbridge. Blists Hill is a faithful recreation of a town at the turn of the century, with drug store, confectioners, printers, chapel (bought mail order from Harrods'!) not to mention the iron foundry and mine works. The place is staffed by folk in period costume who will stop to chat and answer any questions you might have, and you can even exchange your 'modern' money for period equivalents at the bank as you go in. For the record a modern ten pence equates to an old farthing (a quarter of a penny).

Of course, as this was a Doctor Who location, we paid particular attention to the areas of the town which looked as though they might have been used in the show. Foolishly I forgot to take my film schedule with me so was unable at the time to pinpoint the locations used, however, looking at the schedule on my return, it doesn't actually pinpoint them either!

The Mark of the Rani also made use of the Coleport China Museum, which is just up the road from Blists Hill and is, as you might expect, a museum of china. However, once you get through the exhibition rooms, you move outside into a large cobbled area flanked by giant cooling towers. You can see inside the towers, as well as experience the delights of the saggar-maker's workshop (and, yes, you do find out about the saggar-maker's bottom-knocker).

I must admit that the scenes set at the China Museum are so non-descript that I wonder why they bothered - there seemed to be many just as suitable sites at Blists Hill. Be that as it may, we had a great time there, and to cover all the attractions of Ironbridge adequately, you need around three days. Add another day to visit Llangollen, and you have a week-away to suit any discerning Who fan.

**This column has been brought to you by Dapol and by the Ironbridge Gorge Tourist Office**