Sixties companion Wendy Padbury meets sixth Doctor (Colin Baker)

Even in these very un-sci-fi surroundings the magic of Doctor Who lives on. That's what keeps the fans coming year after year to conventions like Blue Box - more than a decade after the BBC axed the show.

It's not just the fans who keep coming back, it's the actors too.

Colin Baker, who played the Doctor's sixth incarnation (1984-86), had brought along his original multicolour costume for a photo session with fans.

Work permitting, Baker attends about six conventions a year.

"It's extraordinary that there are enough people out there who want to come and see the people who made that programme all that time ago, and celebrate it," he says.

Convention hall: Tom Baker hat and scarf not essential

He points out that it was a show that families would sit down to watch together - now something of a rarity.

"In its time it was amazingly innovative, although now we look at the special effects and find them risible. On a small budget Dr Who produced something that we all used to love."

In the convention's Dealer's Room, tables groan under mountains of Doctor Who merchandise. The Time Lord lives on in books, audio adventures and CD-Roms.

K-9 powers down at the end of a long day

"There are more collectible items now than when the programme was on the air," says dealer Dave Willcox, who built up his business after selling his own Doctor Who collection.

His stall includes an array of alien heads - Cybermen, Ice Warriors, evil Dalek creator Davros - which sell for up to £250.

So who actually pays to attend Doctor Who conventions - and why?

Time Lord chic: Fans celebrate the Doctor's bizarre dress sense

Contrary to popular belief, fans who turn up in costume are in a minority.

In fact, most attendees look perfectly normal. Unless they are actually androids about to launch an invasion of Earth starting with the M4 corridor.

But one group of fans - known as The Lords of Time - has turned up in elaborate Edwardian garb.

"It's our tribute to the programme," says Garron Martin from Edinburgh. "It's the enduring concept that's kept it in our hearts."

One group member has even started to earn a living out of Doctor Who. Manchester-based artist Carolyn Edwards has been illustrating the covers of spin-off novels.

"It's really taken off. One of my main reasons for coming to conventions is to sell my artwork," she says.

Artist Carolyn Edwards shows the sixth Doctor her portfolio

While various faces from Doctor Who's past are materialising in the main hall, the Doctor Who Appreciation Society (DWAS) is busy recruiting on the upper floor.

Sarah Fowler, the outgoing co-ordinator, explains that DWAS has nearly 2,000 members from as far afield as Singapore.

"The audio adventures and books are keeping Doctor Who alive," she says. "and the 1996 Paul McGann movie did a lot to stimulate interest. Of course, people who grew up with programme are now forcing their own children to sit down and watch it."

DWAS is celebrating its own 25th anniversary with a one-day convention in London on 26 May.

The skirts got shorter for Victoria (Deborah Watling)

The convention atmosphere is one of a family reunion, although many of the anecdotes have been heard before.

Actress Deborah Watling, who played Patrick Troughton's assistant Victoria in 1967-68, admits that coming up with fresh memories can be problem.

"I got onto the convention circuit in the mid-80s. Pat Troughton said to me: 'You've got to do this, the fans are missing you.'"

Watling says the female assistants were designed to appeal to the dads.

Deborah Watling attends about six conventions a year

"I started out in a long Victorian frock, but the skirts got shorter and shorter and I ended up in a pelmet."

When Victoria left the Doctor's Tardis in 1968 she was replaced by Zoe, played by Wendy Padbury.

Padbury, now a theatrical agent, is making a rare convention appearance after an 18-month break.

"There's a convention almost every weekend somewhere in the country and I had to make the decision to have my weekends off," she says.

But she does enjoy the friendly atmosphere.

"Everybody knows everybody - it's like one big party."

Time to go home ...

Minutes later, Wendy Padbury is on stage recalling her encounters with rubber aliens from the 60s.

She also has an embarrassing admission to make after hours of signing autographs.

"When I checked out of the hotel I signed my credit card bill and put a kiss after it."

Colin Baker has a worse tale from a US convention.

"Someone asked me to sign their pet, they'd even shaved a patch of fur - I declined."

Doctor Who monsters are strange, but Doctor Who fans can be stranger.

The Blue Box IV convention raised almost £1,000 for charity.