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Espionage and intelligence are the stuff of myth and legend - exotic globe-trotting lifestyles, glamorous affairs, and coolly delivered violence is never far away - but how far from reality are these depictions? Quite far, it turns out. Dig a little deeper than Bond or Bourne, and the life of an MI5 spy, while interesting and fiercely rewarding, isn't much like the way the movies would have you think. A former MI5 spy, Annie Mahon, told The Telegraph that she found it hard to get used to the new lifestyle.

The feeling of unreality and dislocation is strong for the first few weeks on the job. The only solid information you have about your new position as you walk into the office for the first time is the grade at which you will be working, nothing else. My first posting was to the small counter-subversion section, F2. Even though it was a desk job, the information I was dealing with came from sensitive sources: intercepted communications reports from agents who had penetrated target groups and police reports. And yet, within a few weeks, handling such secret and intrusive information became entirely normal.

A spy who didn't give her name because she still works for MI5 told Stylist Magazine that much of her work involves analysis and surveillance. I'm working with sensitive information, and there are people out there looking to exploit that potential. Fewer than ten people in the world know what I do, and they include close girlfriends and my ex-boyfriend. She added that her parents struggled to manage knowing she was a spy. They couldn't tell their friends [when I got the job], they couldn't tell anyone looks at what my daughter has achieved since.

That is hard on them. Being a spy is a part office job, part self-facilitating intelligence gatherer. You'll physically be based at either MI5 headquarter at Thames House in London or one of the agency's satellite offices for much of the time, with a high degree of travel, both overseas and domestically. You'll typically rent a property near your office so you can get to work quickly if required. Much of your work will involve working on case files, communicating with colleagues and attending briefings. You'll also have contact with agents and assets, especially if you work on anti-terrorism cases. You may also work in the field, where you could even be required to infiltrate groups, befriend potential targets and gather intelligence on the fly.

Five things every MI5 Spy needs to have

Cover story

Many agents use a cover story that is close to the truth but not quite. Data analyst, civil servant, police officer, military training; these are the sort of roles that a spy could feasibly fit into, and that would seem plausible to an outsider.

Unremarkable persona

Spies need to blend in. They need to be forgettable, difficult to describe and mediocre. Dennis Rodman would not make a good spy. To cultivate this unremarkable persona, an MI5 must shed their extraversion, avoid distinctive clothing, cover (or even better, never have) tattoos - find out why MI5 will halt your application if they don't like your ink - and conceal any distinguishing features, like scars.

High boredom threshold

Much of what a spy does is arduous, relentless research—monitoring movement, tracking targets and analysing the data. It's not all high-octane car chases and cocktails in 5-star hotels. You'll need to be able to tolerate repetitive tasks.

Nerves of steel

Michael, an active MI5 agent, told the BBC: "When you're in some dusty outpost in semi-governed space, about to meet for the first time a contact within a terrorist organisation you've brokered, that is nerve-wracking. There are risks involved in everything we do. I don't think we'd get very far if we were risk-averse. We have to do what we can to mitigate them."

Good spy quipment

You'll have access to a wide range of surveillance equipment, such as spy cameras, listening devices and GPS trackers, and you'll need to know how to use and maintain them. You're only as good as your equipment.