Don "The Brain" Toddington

An imposing Rottweiler who is actually a Royal Engineer with a specialty in communications and generally a nice guy. Has a tattoo of a bleeding dagger on his right upper arm.

The Brain primarily works at GCHQ with the Governor as a driver and bodyguard/grunt, collecting exploitable tech geeks for the "Dirty Half Dozen" project.

When Nathan is hospitalised following the Chicken incident, Brain stands guard outside his room to keep the doctor from leaving on the Governor's orders. While the Governor shouts at Nathan about the inconvenience of having to blindfold paramedics, Brain offers Red some earplugs and asks her not to listen. Once the Governor returns, he demands to know if Red is the only person to see Nathan awake, then makes her an offer: either she continue to be the only one to see the patient and be well-paid for it, or suddenly find her bank account drained just when she gains a mysterious criminal record that was withheld from HR. Red immediately protests that the second is impossible, but to scare her, Brain instantly concocts a trumped-up charge of drug counterfeiting and links to child sex trafficking to use to freeze her assets.

After the Governor and Kevin leave, Brain remains on guard duty to ensure both Red doesn't leave and Nathan doesn't spill any confidential information to her. After an hour or so, he is greeted by Heart and Gates, claiming to be Nathan's solicitor and a florist. When he questions Gates about not having flowers, Gates stuns him with a cattle prod. Gates then has Brain dragged off by the hospital staff "since that bird bit him!"

Brain accompanies the Governor and Steff to an industrial unit rented out to "Mr. Wan Kerr" after the Oracle discovers someone trying to ping his code from within the U.K. He questions the Governor's lack of warrant but is immediately assured warrants aren't required "to make someone just... go *AWAY*."

Brain notices there are lots of computer fans in the storage unit, and the Governor quickly discovers a server farm in the upper part of the unit. Brain offers to start cataloguing everything, but the Governor wants to see if there's anything work taking first. Steff points out that to find out where the proxy server is redirecting, he will have to get "hands-on" and risk tripping any security that might trash the evidence.

Meanwhile, Brain finds and cuts a small opening in a box stored beneath the servers, horrified to find all the boxes there are filled with enough ANFO to "put a *DENT IN THE WORLD!*" The Governor decides it is better to beat a hasty retreat, but not before Steff literally trips a wire that activates a bomb set to go off in sixty seconds.

The three run for it, taking shelter behind a short brick wall some distance away. However, the bomb fails to detonate after three minutes, which leads the Governor to question whether the bomb is real or a dud. Brain trusts the bomb is real but suggests the timer is suspect. The Governor concedes they will have to call the bomb squad, but before Brain can make a suggestion, the bomb finally goes off, bursting Brain's eardrums.

Before Brain's eardrums can heal, GCHQ receives a mysterious package that neither Brain nor the Governor know what it is, although Brain suggests it's something expensive that Q should have a look at. The Governor then sends Brain home because Brain's shouting is giving him a migraine.