Even before Bingham McCutchen cancelled this month's partner retreat to Arizona, the firm was forced to pull some 25 invitations. The reason: the near-wholesale exit of the firm's London and Frankfurt offices – and a handful of lawyers in Hong Kong – to Akin Gump Strauss Hauer & Feld, a move which was completed on 18 October.

It was a remarkable coup for Akin, and a huge loss to Bingham, currently in crunch talks over a merger with Morgan Lewis & Bockius. In total, more than 50 lawyers made the move to Akin, with just competition partner Frances Murphy and one associate remaining at Bingham in the City.

There were several key factors to pulling off the deal, say Akin Gump London managing partner Sebastian Rice and ex-Bingham City chief James Roome (pictured) – now Akin's senior partner in London – as the pair explains to Legal Week the combined offices' new strategy.

"It's a very integrated team, built around one another," says Roome, sat in the 41 Lothbury office which transferred to Akin together with its lawyers. "The practice Venn diagrams and individual partner practices have a good degree of overlap. I think that's different to a lot of firms."

The office structure also certainly helped with the team's mobility. Though similar to Akin Gump's Ten Bishop's Square team, the Lothbury group's leverage model is also fairly distinct, in that it has roughly the same number of partners as associates and counsel combined. "We don't really care as long as we have got bright alert people," says Roome. "We charge high rates to give the best quality advice."

Furthermore, the team Roome built was somewhat distinct to the rest of Bingham's business. "Between 85% and 98.5% of what we did was self-originated," he adds. "That gave us the independence to do [the move] and to work as a group."

For such a tight-knit group of partners – one ex-Bingham partner described the London office as "a firm within a firm" – one of the challenges now will be to successfully blend into the Akin fold, given the heightened sense of loyalty with which lawyers in the Bingham group view one another. Being based across two offices for the time being may hinder that.

According to Rice, that potentially difficult integration is underway, and the offices have already married their recruitment processes across a number of practices. "We had a big party in the atrium downstairs last month which was attended by 130 people. You couldn't tell who was from the old and new offices – everyone was mixing," he says. Firm chair Kim Koopersmith made the trip especially, the latest of many visits to London this year. "Once the [Bingham] opportunity was identified, she would not rest until the deal was done," comments Rice.

Roome dismisses suggestions the deal involved any sort of guarantee. "It's just not necessary; the world is changing. I took a guarantee when I went to Cadwalader, and I swore then that I'd never do it again, as I just think they don't work." Turning to Rice, he adds: "Maybe we should be guaranteeing you guys, not the other way round." Given his team is on track to beat last year's profitable financial performance – alongside the transfer of the office's client base – this seems like a reasonable offer.

When Koopersmith spoke of an investment in the group, Rice and Roome suggest she meant the cost of partner hours in cementing the integration, rather than any onerous lease commitments.

And for the legacy Bingham office's restructuring and funds teams, increased collaboration with Akin's US lawyers may also be the boon they were seeking. "A lot of the grand fromage types [at Akin] are coming to visit us," says Roome. "For us that is quite a change that they are so excited to come over here, and great to see. That's what we were banking on, getting clients involved in corporate activism and European restructurings that need to go through the US."

"There are big energy opportunities for the Lothbury team as well," adds Rice. "Obviously there are huge benefits to Akin in the financial restructuring team, and antitrust strength is something our clients have been asking for in London for a long time."

And while restructuring work may have dipped in Europe in the last two years, Roome is confident that distressed assets from the period's high yield bond bonanza will be a major source of work for the integrated office in the next few years. "Every time I meet with our private equity or hedge fund clients they ask when the market is going to turn," he says. "It's not a case of if, but when it's going to happen." He also points to the Frankfurt team's strong profile in corporate work-outs in Germany, which – amid a downturn in the Mittelstand – he says is beginning to show signs of a significant pipeline.

As for the current state of Bingham McCutchen, its leadership and US media reports that it may consider bankruptcy if the Morgan Lewis deal falls through, Roome declines to comment. But the consensus within the legacy London office is that Bingham did too many mergers and made too many guarantees in the last decade, creating a loss of momentum and confidence in the partnership at large.

For Bingham, the London, Frankfurt and Hong Kong exodus was the biggest sign of internal concerns over the firm's integration and merger strategy. For Akin, making that strong-minded team fit alongside its less high-profile legacy City office is a challenge that will likely keep Koopersmith, Rice – and Roome – busy for the foreseeable future. If not quite as busy as Bingham and Morgan Lewis' leaders.