It was supposed to be a surprise outing for myself and my eldest Junior Research Assistant and, to be fair, I didn’t click even when we drove on to the local industrial estate at Treforest. In fact, it was only as we rounded the corner to the anonymous blue warehouse and I spotted the letters “BBC” on a warning sign that I realised this must be the location of those studios … which must mean we were going to see something from … that show … which was really kind of … oh wow. OH WOW! Somewhere back in 1975, a small boy watching Tom Baker would probably have felt the psychic echo of my sudden excitement thirty-six years in the future.

At the entrance, our small party was met by Gaynor, the Facilities Manager (who coincidentally is related to one of my Glamorous Research Assistant’s colleagues, hence the favours begged and strings pulled). She apologised for the fact that she didn’t have much to show us anymore, as the facility was in the process of being shut down following completion of the Doctor Who Christmas special for 2011. Production was transferring to the new Roath Lock studios in Cardiff Bay (where they are already filming Casualty and are due to start Upstairs Downstairs shortly). Torchwood, of course, had “gone to America” and the Sarah Jane Adventures have sadly wrapped up for understandable reasons. The corridor along which we passed by the three main edit suites was lined by posters from all three shows, including a rather cool one of the huge Dalek Emperor from The Parting Of The Ways.

The Daleks had apparently moved out the previous weekend. Nevertheless, there was still one significant prop left in the studio - a set that plays almost as important a role as the titular main character. A really big, in fact larger on the inside, set which can be accessed either via the cameraman’s entrance at the rear, or via two elegant yet unassuming pannelled blue doors at the front: PULL TO OPEN… and yet of course, one pushes…

Once inside, it is - let’s not underplay this - approximately as amazing as if it were the real thing, and you had been invited to go inside by its owner. I haven’t been to the Doctor Who Experience yet so I don’t know how their TARDIS compares, but the studio set, even under house lights and shorn of effects and dressing, will instantly transform you into a speechless, awed fanboy and your children into delighted proto-Time Lords. In the middle sits that console in all its mad, eccentric jumble of office spares and junk shop bargains. Around it are plush leather car seats and railings and steps and platforms and roundels and mysterious corridors, while overhead are the odd concentric circles of what appears to be a mutant modernist light fitting, which the central column rises to meet. On the edge of one panel of the console, in all likelihood never seen and never going to be seen on the show, was an “authentic” maker’s plate, identifying the vehicle as a Type 40 TARDIS constructed at the Gallifrey Blackhole Shipyards in 1963, and warning that it was authorised to be piloted by “qualified Time Lords only” (and their family members, presumably).

Two of us ran excitedly from panel to panel of the console, pulling all the levers, pressing the typewriter keys and the keypad buttons, spinning the rather odd ball of sonic screwdriver leftovers, before budging together on one of the seats in breathless, wide-eyed delight. The adults wandered around in a euphoric daze, trying to make vaguely sensible conversation with Gaynor and all the while thinking, “HE stood here! Where I am now! Touching THIS lever!”

Coming back to earth slightly, I was struck by how carefully it must be lit and filmed, how much time spent selecting the right angles to portray the action, as so much of it is so clearly and obviously just a set. Those mysterious corridors don’t get you much further than a serious healthy and safety incident, as large parts of the background are simply missing or are precariously railed off with scaffolding. Become carried away by the action, charge ahead and take a wrong turning, and you could quickly find yourself suspended in thin air, for a brief moment. At least a fifth of the outer surround is missing or only sketchily constructed, presumably for ease of access with the filming equipment and crew.

The containing warehouse is lined with miles of black curtain to deaden the acoustics (all sewn by Gaynor). The entire shell is surrounded and braced by steel girders, which are bolted to the floor. It was for these reasons, and because of its immense immovability, that this TARDIS wouldn’t be rematerialising in Roath Lock, instead being reconstructed afresh on site. However, we were given to understand that an expendable duplicate such as this was not yet considered redundant for filming purposes…

After a while… um, some considerable time actually… we regretfully left the TARDIS and walked across the road to the other building (past the “Blue Box Café” portacabin which provided the on-site catering). This appears to house the props department, and in one crammed room we found shelves piled high with enough heads and body parts to rival an average size morgue. Miscellaneous Hath, Slitheen and Sontarans gazed down from above as the JRA and her friend each tried on a Cyberman glove. There were a couple of cast-off Weeping Angel skirts, while a troop of Cyber torsos were piled haphazardly across the other side of the room, in front of a life size dummy of the Tenth Doctor (his wig askew apparently because the janitor had been trying it on the week before). In a box before the door, well placed to freak out the unwitting visitor, sat the pasty, bloated body and blank gaze of one of the abducted Children Of Earth from Torchwood.

After a good, long nosey, we set off back to the main building, where Gaynor presented the two girls with a poster, promotional postcards and a magazine each. It strikes me that, whatever the daily crises, politics, rivalries and varying alliances that may occur behind the scenes, everyone who works on this show is acutely aware of what they are stewarding and of what it means to those who watch it. Throughout our visit, Gaynor was unfailingly patient, indulgent and generous to all of us, whether reverent and dazed or giddy and excitable. I can’t speak for the JRA and her friend - we’ve been trying to explain to her that not everyone gets to stand in the “real” TARDIS - but this was certainly a day that BB won’t forget.

Other bubbles

• Flickr set of some photos from the visit.