Leslie Perrin is managing partner of Osborne Clarke. He can be contacted at leslie.perrin@osborneclarke.com

I am as baffled as a trainee in a magic circle firm who has been given a weekend off. The cause of my confusion is pro bono work. While I admire the dedication of lawyers who work pro bono, I am transfixed by the "official" definition of pro bono work given by the admirable Solicitors' Pro Bono Group. Apparently, it is the task of pro bono to get good quality legal advice to people who would not normally have access to it such that an improvement is made to their lives. I can't help thinking that this is why the UK developed its system of legal aid, which is now in the process of being dismantled by the government.

Paradoxically, the pro bono movement proudly points to Government ministers actively promoting pro bono work by lawyers while barristers warn that the criminal justice system is now so dependent on lawyers working pro bono that it would be unable to function without them. Does nobody hear the beat of the Treasury's cloven hooves? Bets, anyone, on further legal aid cutbacks again to be financed by the legal profession, this time through pro bono work?

And now it seems that for some law firms, the real value of pro bono work may lie in its potential as a marketing tactic. As every multinational knows, communicating the ethical purity of corporate decision-making is one of the main drivers of the status of the corporate brand. On face value, then, pro bono could be a good strategy for law firms, which need all the help they can get in convincing the public at large that while men may be from Mars, lawyers aren't necessarily from Uranus.

So does this mean that we are entering a phase where pro bono is not so much by and for the good of the people as by and for the good of PR? In terms of sincerity, this approach is about as credible as the guy who watches Baywatch for the articles. One challenge that its practitioners must not ignore lies in ensuring that pro bono is not some cynical gesture of noblesse oblige but genuinely constructive action.

My starting point on firms' duties here is simply this: commercial lawyers – who can earn double-figure multiples of the national average wage – have a duty to make a tangible return investment into the communities from which they draw such ample livings. What needs to happen is a genuine grass roots interaction of law firms with their communities that is sufficiently organic to blur the distinction between motive and result.

It's my experience that the most enriching of these activities spring not from a firm's management or marketing teams, but from the ultimate purveyors of its corporate brand: its people. The sheer variety of their endeavours (including but not limited to pro bono work) and the energy with which they are pursued can be truly humbling and any law firm worth its salt will put serious resources behind its people in support of their commitments.

As part of this, it may, of course, be appropriate for law firms to support the Solicitors' Pro Bono Group, but not if by doing so they feel discharged from their wider community responsibilities. And there is a danger in the group allowing the suggestion to hang in the air that non-member firms are neglecting their community duties – at the same time as the marketers embrace the bleeding-heart-on-sleeve approach and the Treasury continues its dirty work on legal aid.