Earlier this week Berwin Leighton Paisner (BLP) elected its first ever female managing partner. The vote of confidence in Lisa Mayhew means she joins the small but growing band of women at the helm of a leading City law firm.

Within the UK top 20, she and Herbert Smith Freehills' Sonya Leydecker are the only females holding managing partner/chief executive roles, with Addleshaw Goddard's Monica Burch joining the table when taking into consideration the more ambassadorial senior partner position.

Beyond this, in the top 30 there is CMS Cameron McKenna senior partner Penelope Warne, Stephenson Harwood CEO Sharon White and Withers managing director Margaret Robertson.

Assuming each top 30 firm has both a managing partner/CEO and a senior partner/chairman, you're talking about 60 available positions, with women holding six of them. On one hand, just 10% of senior leadership roles being held by women is a dreadful statistic given the numbers that enter the profession at the junior end. On the other, advocates for change will be encouraged by the fact that three of these appointments have been made since last May and the bulk in the last five years – suggesting the trend is gathering pace.

In the case of BLP, it is hopefully a sign of a firm putting into practice what it preaches and being willing to change. In Mayhew the firm has elected a partner who only joined in 2010 to succeed one of the most longstanding law firm managers around – a fact that is far more surprising than her gender, and indicative of an openness to new ideas that it would arguably be hard to find elsewhere. (Charlie Geffen's ousting aside, how often are law firm election results that surprising?)

And it's hard to think of a better way in which the firm could have shown its commitment to the gender diversity targets it set last autumn – to have a 30% female partnership by 2018. Assuming Mayhew is given the power that should come with her new title, and is not overshadowed by outgoing managing partner Neville Eisenberg in a yet to be confirmed new role, her appointment should be seen as a huge positive both for the firm and the legal sector.

Quotas and targets are a controversial topic – of course people should only be given positions they deserve and are capable of. Drawing further attention to what remains a significant problem in the profession and providing tangible examples of how it can be rectified, though, can only be a good thing.