BBC Cymru Wales surpassed all expectations with their eagerly awaited Roath Lock open weekend on March 10-11 (writes Chris Williams).

From 8.45am on Saturday, eager fans entered the world of TV production and witnessed first-hand some of the secrets of creating fictional worlds and making them look believable!

Each tour started with a welcome which only served to heighten excitement and left visitors almost literally straining at the leash. A neatly edited video then further tempted the crowd, as familiar stars from Casualty, Doctor Who and Pobol y Cwm shared some of the facts and figures of the BBC’s newest and largest studio production complex.

Doctor Who’s Arthur Darvill and Matt Smith set a light and cheerful tone for this; Charles Dale and Derek Thompson then provided a theatrical performance that left us in no doubt about Roath Lock’s green credentials.

Did you know, for example, that all of the toilets in the complex flush using rainwater?

The studio tours were simply thrilling. Firstly to Cwm Deri, home of Pobol y Cwm. Within just metres of the complex’ perimeter, we suddenly found ourselves in West Wales, with real, full-scale solid brick buildings - complete and realistic in every detail.

Sioned’s shop with up-to-date newspapers and an estate agents with real houses on sale, and the village pub Y Deri looking every bit as it does on TV, and completely real!

The attention to detail was phenomenal, as it was too in the internal, studio-based sets.

Then, round the corner, Cwm Deri became Holby, and there was the ambulance bay complete with three ambulances, a fast response paramedic car and a bike.

We’d entered the world of Casualty! It took a couple of blinks to realign perception, but a brand new hospital, complete with all expected fixtures, lay in front of us - in the heart of Cardiff Bay!

We saw the familiar sight of reception, triage, the CT scanner and wards with fully-functioning hospital beds. A pharmacy packed full of drugs - and everything you’d expect to see in a real casualty unit! Only the lack of that ‘hospital smell’ reminded us we were actually in Roath Lock!

With patient folders and notes, copies of the Holby Gazette lying around, and computer screens updating with appointment scheduling, the BBC really had gone the extra mile in creating a convincing vision of a fully-functional hospital, and a medical specialist was continually on hand to aid with the realities of hospital life and medical procedures.

From Casualty to a general exhibit of props and, after being blasted with smoke and fake snow by the SFX team, a Doctor Who Ood, complete with communication ball and blinking eyes greeted us and offered a very gentile handshake!

Of course, the TARDIS was a centrepiece, as was a rather menacing Dalek, surrounded by enchanted fans of all ages. We witnessed first hand the work of the BBC Wales prosthetics team and met its chief, Neill Gorton.

From amputated legs with pulsing wounds, cadavers afflicted with hideous injuries, to a wealth of Doctor Who monsters and ‘soft props’, it was all there.

A cricket bat used in a murder was really made of foam, and a collapsed wall looking all brick was actually spongy in mass and texture. Visually perfect, but so different when felt or held.

Concluding the tour, we had an opportunity to chat with the team responsible for Doctor Who online, along with the geniuses responsible for a plethora of online games and other digital media.

Sherlock fans had a chance to wear that famous Deer Stalker and to see some of the costumes in the show, and Upstairs, Downstairs finery was also on display.

It really was a fantastic opportunity to get a chance to see BBC Cymru Wales’ Drama in action, and what we saw was a salient reminder of the fact that good TV doesn’t just ‘happen’ - and that what needs to occur behind the scenes is immeasurably more than what most of us believe!

Dinas Powys resident Chris Williams writes a blog focusing on BBC Wales drama / SciFi) - read it at www.facebook.com/TheTimeKill