"We are pretty close to having more international offices than UK offices," says DWF managing partner and CEO Andrew Leaitherland, as he sets out the firm's plans following its high-profile hire of former DLA Piper leader Sir Nigel Knowles (pictured above).

Following a period of rapid expansion, the UK firm has turned its attention overseas in recent years, entering 10 new cities in some capacity since January alone.

And while Leaitherland will not be drawn on where DWF plans to go next, it is clear that Knowles' past experience at DLA makes him well placed to help drive the firm forward.

Since January, DWF has gained a presence in Chicago, Sydney and Toronto through its acquisition out of administration of claims management business Triton, in addition to sealing associations in Jeddah and Riyadh in February and acquiring teams for office launches in Paris and Berlin. The firm also entered Singapore in June, and Bogota, Panama and Buenos Aires in July through associations with local firms.

Now in his fourth term as managing partner, Leaitherland has overseen this wide-ranging geographical expansion, and has been open about his desire to establish the firm among the UK top 20 by revenue.

While the firm spent two years in this bracket after surging up the rankings in 2012-13, when it almost doubled in size on the back of five mergers, it has subsequently slipped just outside of the top 20. However, Knowles' hire – a very rare example of a major law firm leader taking up a similar role at a rival firm – provides a welcome boost, and a clear indication that DWF's expansive ambitions are by no means satisfied.

I don't believe there is anything I have done before that I would want to do again at DWF

Knowles is joining the firm as a partner as well as chairman, having most recently served as a global ambassador at DLA Piper and High Sheriff of London, after stepping down as global co-chair and senior partner of the transatlantic firm last year.

He says the first discussions about him becoming chairman at DWF took place in June, and that he is looking forward to a new kind of role – one in which he is not responsible for strategy, but will instead see him focus on clients.

Knowles explains: "I am chairman, not managing partner, because that is Andrew's job, and therefore I am not there to initiate or execute our strategy. I like the concept of connected services and delivering to clients what they want and not what you think they want.

"I stopped practising the law 21 years ago, so when I bumped into a client, my conversations were not about the nuances of M&A activity, they were always about business. Businesspeople don't think about how English law is practised; they are looking for a firm with a competitive advantage. When you discover how clients work, you can put those lessons into practice and shape up so that your clients want to instruct you."

Leaitherland (pictured) adds: "From our perspective, the massive appeal of Nigel is his mindset, his client-centric approach and that he can give us an ambassadorial role. Our strategy is set: we are looking to globalise our services in insurance, financial services and real estate and get more services under one roof. It is about providing a full approach for our clients – gone are the days when clients want to manage 20 or 30 relationships."

Leaitherland says DWF has always looked outside of the firm for its chair. He explains: "We have always had an external chairman because we see the benefit of somebody coming in from outside with a new eye. Nigel and I have been in regular contact for a couple of years and the timing just coincided, when I had a conversation with Nigel just as [former chairman] Alan Benzie was leaving."

Knowles jokes: "I have been aware of Alan Benzie for more than 25 years and I have also known Andrew for a long time. Every time I saw Andrew, I would ask if he had got rid of Alan yet. Then Alan said he was looking to step out as chairman at DWF and asked me if I would be interested. Under Andrew's leadership, DWF is exactly the sort of firm that excites me."

During Knowles' leadership, DLA Piper grew from a regional Sheffield-based partnership into a global player through its 2005 merger with Chicago-based law firm Piper Rudnick and San Diego-based firm Gray Cary Ware & Freidenrich.

After two decades at the helm, Knowles says he wanted a new challenge, as his former firm had moved on during his time as High Sheriff to the point that returning would have been too much "like having your dad around all the time".

Instead, he will now lead a review of DWF's strategy to ensure that he is satisfied with it – although Leaitherland insists that nothing fundamental will change.

As chairman, a role with no set term, Knowles says he has no interest in mimicking the decisions he made while at DLA Piper.

"We are in a different moment," he says. "We are in a moment where technology is really at the fore; the future is about listening to clients and embracing technology. I don't believe there is anything I have done before that I would want to do again at DWF, as the thinking has moved on. Secondly, DWF is not intending to be DLA, and nor should it be.

"The business is in great shape and the real secret is to prioritise in the right way to make the most out of the opportunities that are available to us. Clients don't want an execution-only firm, they want to feel that you are on their side. That comes through speaking to clients, and that's what I hope to bring."