So you want to be a lawyer? Have you ever asked yourself why? And you want to work in the City, working for Big Law? Have you really really asked yourself why?

If you are a regular reader of my blog or follow me on Twitter, you might think I'm a little averse to Big Law LLP or to outhouse in general. I'm not really. It's just a bit of banter with some serious points thrown in. As someone who trained at Big Law (Denton Hall, in the days when it had arguably the best media practice in London) there are many positive things to say about Big Law as a place to train and indeed practice: great training; technically excellent lawyers; sector specialists beyond measure; big brand clients; cutting edge work; big deals (if that's your thing); a certain atmosphere which, like it or not helps instil a sense of discipline and professionalism appropriate to being a lawyer; and let's face reality, it pays law school fees and a decent starting salary.

So if there is much to be said about training at Big Law, why am I writing a blog post challenging the reader as to whether it is the right thing for you to do?

Thankfully I am not often asked why I became a lawyer. On the rare occasions I am, I'd like to express a passion since birth for the importance of intellectual property to the economy and for freedom of expression, but that would not exactly be true. I knew nothing much about either of these things until well into my training contract. From what I remember of my university cohort I was far from the only student who held such indifference. Like most of my university contemporaries, I'd decided to read law because it seemed like 'a good thing to do' at the time and then towards the end of the second year got swept up in what they used to call (and maybe still do) the milkround. The milkround was my first introduction to City firms, where the glossy brochures and promises of what seemed dream-like starting salaries for a glorified Photocopying Administrator (albeit with the potential for promotion to Processor of Company Searches in my third seat) proved very attractive.

I don't remember much career advice at the time or encouragement from my University to consider alternative routes into law, such as the Bar, criminal work, legal aid practice, niche practices or even alternative careers in business. So it was that in our final year of University my contempories and I would bandy around names like Ashurst Morris Crisp and Simmons & Simmons as if we'd been considering them and other Big Law firms as potential employers since the age of five.

In truth, I had no passion for becoming a lawyer before I joined the profession. To be totally candid, I had no real passion for many aspects of it until I moved in-house, it was only then that I found what sparked my interest and motivated me. I've asked myself since, what would have happened if I hadn't moved in-house, at the right time, to the right employer? Would I still be practising law? And if so, would I be enjoying it? I think the answers are "maybe" and "no".

I compare my then student and trainee self with bloggers Benjamin Gray, Ashley Connick and the anonymous Miss TS. Three young people whose passion and interest in different aspects of the law and the legal profession, even at such an early stage of their careers, is such that they are moved to write about it. When I was a student or even a trainee, I wasn't interested in much beyond finishing the next bit of revision/research, having a beer with my friends and playing a bit of football (badly). Don't get me wrong, I worked hard both as a student and a trainee and was very conscientious. It's just that I wasn't much interested in law beyond doing what I had to do as well as I could. The idea of spending non-curricula time writing or thinking about it would not have entered my head. Thankfully that mind-set changed for me when I moved in-house at an early stage of my career.

Take away strict academic standards which I'm not qualified to write about, my anecdotal experience as a recruiter in the legal market and an observer of legal developments, is that student standards have improved beyond measure since my undergraduate days. I don't mean the academic intelligence of students, I mean emotive intelligence and what you might call world experience. Younger lawyers these days invariably have a list of impressive non-academic achievements as long as your arm and equally impressive work experience to boot. The would-be trainee of 2011 needs far more than a 2(i) from a decent University, being a "member of the Law Society" and a 2 week work experience placement at the high street practice near their school in order to get a job in a City firm or decent set of chambers. They need a genuine interest in law as a career well before that career starts and with that interest comes a far better understanding of what being a lawyer really entails then I expect most of my peers entering the profession had in the early 1990s.

And this, is a good thing. And it is why, if you are a student reading law and who is only toying with entering the profession because you can and because it seeks the easy thing to do, rather than because you want to, really really want to, that I encourage you to think hard about your choices.

There are plenty of good and positive things about becoming a lawyer at Big Law. But make no mistake, there are plenty of negative things too: the hours can be rough; you are beholden to the client; a lot of the work can be mundane and repetitive; it is competitive; law firm structures are inherently hierarchical and the hierarchy gets reinforced regularly; the mediocre moments far outweigh the genuine adrenaline inducing high points; and achieving a satisfying work/life balance, particularly if you have a family, is a challenge. If you want to be a lawyer, you should be cognisant of these things and want to be a lawyer in spite of them, not in ignorance of them.

If you are a law student or a trainee do you blog about law, write about law, tweet about law, take part in moots or in some other way spend, out of choice, any of your own personal leisure time doing something connected with law, because you want to? If not, I suggest you think very hard about whether a career in the law is right for you. Because let's face it, at interview, you are going to be up against the Benjamins and the Ashleys. And not just at interview either, you're going to up against them when you are training, when you are learning, when you are building your own practice. If they can be bothered more than you can now, won't it ever be thus?

And it's not just the Benjamins and Ashleys either. It's their equivalents across the world – in India, China, South America, the Middle East. A couple of years ago I was in a hotel in India with a colleague on a business trip. We were discussing how our children were getting on at school. Looking at the Indian business men (and in India for the most part it is sadly correct to say business "men") swanning around the hotel with their various entourages, my colleague said something that stuck with me: "It's not the kids in your kids' class they are going to be competing with for jobs. It's the kids in school in China and India who are the real competition." The world is shrinking by the day.

In Twitter speak, I'm #justsaying that there are other careers out there to consider. Or at least alternatives to being sucked by default into the commercial world of Big Law. You should consider them, look at them, experience them, and make an informed choice. You want a job that is going to maintain your interest. Look around Twitter, look at the lawyers on Twitter who come across as passionate about their jobs, not many of them seem to come from Big Law. You don't find many securities or real estate lawyers blogging about the joys of being a securities lawyer or a real estate lawyer (Barry Gross, of course, being the excellent exception that proves the rule in the case of real estate!). If you want to go and work in Big Law having thought about it, then great, it offers an excellent career. But do it because you want to, not because you turned up to a milkround and it seemed like the easy thing to do.

Is there a risk that this is all a bit negative and discouraging? Maybe, but that's not my intention. My point is, if you're going to go for law as a career, do it properly. Give yourself a competitive advantage before you apply for jobs. Have a clearish idea of what you think you might be interested in doing. Don't end up at Big Law for the wrong reasons because before you know it you will be qualifying and unsure of how it came to pass that you are now a financial services regulatory lawyer approaching partnership and earning too much to say stop, I want to get off the ride now.

I was fortunate, in that despite my relative indifference at an early stage in my career, I ended up practising law in a sector I am passionate about, interested in and at a fantastic company. And there will be many others like me for who it all worked out despite such early indifference. And I'm not saying that it's impossible to do it that way today. Just that it is more difficult, there is more and better competition and I think employer's expectations are higher at an earlier stage. Fifteen or so years ago I wasn't competing against students or trainees who wrote, blogged and Tweeted about law. Unfortunately for you, you are. It's game raising time, and it is only worth raising your game if this is what you really want to do.

The totality of legal careers is not Big Law. The totality of potential careers is not being a lawyer. Just think about it. And if you go for it, the very best of luck. The legal profession, including Big Law LLP, can (despite the caveats highlighted above) reward you with a enjoyable, rewarding and intellectually stimulating career.

Tim Bratton is general counsel of the Financial Times and blogs at thelegalbratblawg. Click here to follow Tim on Twitter.