While the logic of DLA Piper's appointment of ex-Linklaters head Tony Angel isn't hard to fathom, it turns on a gamble which no-one in the legal industry knows the answer to: can you bring in an experienced lawyer to lead (which largely means change) another major law firm?

We're in the field of educated guesses, so little tested is the theory. Though common in public companies, the received wisdom in law is that you can't get the political capital necessary to lead without first putting in years as a successful partner. (Angel's reputation as a leader now so totally overshadows his achievements as a practitioner it is forgotten that he was a highly formidable tax lawyer; Steve Edge at Slaughter and May wrote a letter of thanks to Linklaters for promoting a key rival out of client work).

Certainly, comparable attempts to draft in non-lawyer chief executives to run major law firms do not bode that well. Still, Angel at DLA Piper is a very different proposition to such moves. If it can work, the combination of one of the most celebrated law firm leaders of recent years with a practice famed for its ambitious non-conformity would look to be where it will happen. The strength of Angel's reputation should go a long way towards giving him the level of instant credibility very few externally sourced leaders could ever hope for and his firmwide brief as co-chairman means he should have the power base of DLA's US partnership to provide ballast.

There are other positive factors. The culture shock should be cushioned by Angel having been out of Linklaters for more than three years and having managed two non-legal businesses. In addition, he will be working alongside Nigel Knowles rather than taking the lead executive role himself – a promising double act if their previous chemistry can be sustained.

But while Angel's recruitment will obviously appeal to DLA's taste for the flashy gesture, success here will be about the hard slog of delivery. Hugely impressive as DLA's journey has been from northern upstart to global challenger, there has arguably been a bit too much flair and not enough rigour at the firm of late. Injecting a new discipline means Angel will have to quickly adapt to a very different – and frankly patchier – partnership than he is used to. And that will be harder with a business that is more entrepreneurial but also less tightly-knit than Linklaters.

And rational as the appointment looks on paper, you still can't discount the sheer disjointing oddness for any lawyer making such a move, given the curious mixture of bonds and emotion that shape law firms. Linklaters, for one, seems nonplussed – and perhaps even slightly hurt – by the move. That cultural jolt will not be easily managed. No-one doubts Angel's ability to deliver on the process, but if he wants to work much magic at DLA Piper, he will have to display equally sharp people skills.