The Sonic Pen

Miss Foster, played by actress Sarah Lancashire, was the antagonist of the story “Partners In Crime”. As seen in the opening episode of Series 4, she ran a company called Adipose Industries which provided weight loss pills and diet plans to overweight people in the U.K. However this was, in fact, just a cover for Foster’s true, ulterior motives as she was really a wet nurse called Matron Cofelia, who had actually been employed by the Adiposian First Family to foster a new generation using Human Beings as surrogates after their breeding planet was lost.

“I've locked the controls with a sonic cage. I'm the only one that can control it. Not unless she's got a sonic device of her own, which is very unlikely.”

This was more likely than The Doctor had expected, as the wet nurse was indeed armed with a sonic device of her own, disguised as an everyday item, to be precise a pen. This was overtly the first time in the show that a Sonic device had been used by a character who wasn’t either The Doctor himself or a companion.

The task fell to the concept artist, Sarah Payne, to design how the pen should look. She used a high end ballpoint pen as a basis that was sleek and smart to fit in with the corporate feel of Adipose Industries offices. After this foundation was complete she created various colour alternatives for the production to choose from, which included red and green coloured variations.

Once this design was approved, prop maker Nicholas Robatto began work making the hero prop. This was made from turned aluminium with sections painted in a gloss black paint finish. The prop was fitted with a sliding emitter section to mimic the extension mechanism seen on the other devices of a similar ilk seen in the show at that time, e.g. The Sonic Screwdriver, Sonic Lipstick and Laser Screwdriver.

“FOSTER: Partners in crime. And evidently off-worlders, judging by your sonic technology.

DOCTOR: Oh, yes, I've still got your sonic pen. Nice. I like it. Sleek. It's kind of sleek.

DONNA: Oh, it's definitely sleek.”

Despite the pen having the ability to extend, this function was never seen in motion during the episode, but the prop is seen statically in both open and closed mode during the story. Once opened a metal cage section with a clear cylinder inside is revealed under the emitter dome, which lights up blue when activated.

Additional stunt props were also made by Nicholas out of resin for the episode. These were used in sequences such as when The Doctor catches the Sonic Pen whilst hanging from the window cleaners cradle and at the end of the story when he throws the device in a public bin.

The Pendants

Alongside the Sonic Pen, two Adipose Industries “Gold” Pendant props were also needed for the story:

“The box comes with 21 days worth of pills, a full information pack, and our special free gift, an Adipose Industries pendant. It's made of eighteen carat gold, and it's yours for free.”

These pill-shaped necklace charms were an integral part of the plot of the episode as they were part of the activation process for the Adipose parthenogenesis, which notably resulted in the demise of the character Stacey.

Concept artist, Sarah Payne created the original conceptualisation of the props, designing them to resemble the adipose industries diet capsules, with screw threaded internals that unlocked to reveal the technology inside.

This design was then once again realised by prop maker Nicholas Robatto, who turned the two halves of the charm on a lathe. Although this was not from the advertised eighteen carat gold, but instead from more affordable brass stock. Rather than having the prop be screw threaded as well, the props were actually push fitted together, which still allowed them the ability to be twisted during scenes. These were then taken away and laser etched with the Adipose Industries logo and completed with a copper loop and gold chain.

The prop had to have some wiring and connectors inside as well to illustrate that these necklaces were alien technology. The internals were made from aluminium, which was then adorned with red and blue wires and finished off with a central, thinner copper wire. This thinner copper wire was used to connect The Doctor and Donna’s capsules during the climax of the episode, when the pair stop Miss Foster’s plan.

“DONNA: Doctor, tell me. What do you need?

DOCTOR: I need a second capsule to boost the override, but I've only got the one. I can't save them”