Be prepared to leave your comfort zone. As a junior partner of Carter-Ruck, I felt that my career was becoming very restricted. The profession had begun to move on from the “know a bit about everything” approach to expecting lawyers to specialise in a particular area at quite an early stage. I also felt slightly on the outside when it came to decision making, which was frustrating, as I’d always been interested in the business side of things. I was in my early 30s, I didn’t want to be doing the same thing for another 25 years, and I decided that it was time for a change.

In a law firm, the business is law. In a company, lawyers are there to help the business achieve its goals. The latter requires a much wider set of skills. Since moving in-house I’ve not only advised on all kinds of legal matters, I’ve also found myself playing a very active role in broader strategy and management issues. Last week, for example, I did a talk about Vodafone’s strategic development to several hundred people in one of our call centres.

Hiding away in an ivory tower isn’t looked on favourably. In-house lawyers are required to give detailed advice based on a thorough understanding of how the business works, so it’s very important that you’re not afraid to get out there and see how people do their jobs. At Vodafone that means doing everything from visiting base stations to understanding how a mobile phone call is connected. Issues come up all over the place and you can’t waste time saying, “Well, I don’t really understand that.”

No fence-sitters allowed. Businesses expect their employees to be decisive and willing to make a call, so it helps to be the kind of person who is comfortable with not being 100 per cent certain about everything all the time. Prior to joining Vodafone, I spent several years at Yahoo!, where one of my roles was to advise on what constituted obscenity. I’d be given images intended for publication on the website and have to take a view on whether or not they infringed the law. I learnt to see the occasional mistakes that I made as part and parcel of the job.

Be able to work fast. I’ve always found timesheets to be a real turn off, so I love the fact that there’s no hourly billing in companies. But you have to accept that it has an impact on the way you work. You don’t get paid more for spending four hours on something rather than two.

“This is all very interesting, but can you put it in English?” Businesspeople really don’t enjoy receiving over-complicated advice. You need to be able to not only interpret, but to simplify and give a very direct steer on what the company should actually do as a result of your advice.

Start thinking about making a move as early as possible. I made my initial move in-house — to join the BBC’s legal department — when I was ten years qualified, but people tend to switch much earlier these days. There’s a window of around three to five years post-qualification experience that’s ideal. At that point lawyers have solid private practice experience, but companies can still compete on salary.

Sample life on the other side. There are loads of secondments available for general commercial lawyers, which are not only a great way to find out if working in-house is for you, but also very useful in terms of building up contacts to help with securing a position in the future.

You don’t necessarily need to have a background in a specific area. At Vodafone the way we look at it is that if you’re a good commercial lawyer you can lend your hand to telecoms. My background is actually defamation litigation. Commercial law is something that I’ve gradually learned through previous in-house positions.

Find an interesting company. I’ve always looked for businesses that are innovative and creative. Technology companies tend to be a good bet. My stint at Yahoo! was particularly exciting: the internet was in its early days, it was quite a small company at the time and it was a great chance to be involved in a business that was very dynamic and growing rapidly.

What work-life balance? At Yahoo! the hours were very long. They were slightly better at the BBC, but at Vodafone I’m in from seven-thirty in the morning until seven at night every day. I thoroughly enjoy my job and I’ve learnt a huge amount since moving in-house, but it’s not an easy option.

Jonathan McCoy is head of the UK legal department at Vodafone

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