Mixed emotions were on display at Herbert Smith's offices last week after months of wrangling over the ownership of client BAA put the FTSE 100 company firmly in the embrace of Spanish suitor Ferrovial.

On one hand, the £10.3bn bid has given the top 10 City firm a lead role on the highest profile City deal of the year. And given the amount of manoeuvering in the drawn-out bidding war, fees will be substantial, even by the standards of big-ticket mergers. The deal, led by up-and-coming partner Gareth Roberts, is also the second-largest transaction Herbert Smith has handled in a lead corporate position, even before taking account of the bid's contentious nature. Neither will it hurt Herbert Smith's reputation that the BAA camp, which included Slaughter and May for Citigroup and debt finance counsel Clifford Chance (CC), was regarded to have played its hand with real aplomb.

But, and it is a big but, a question mark now hangs over Herbert Smith's future role with the airports operator – one of only a handful of FTSE 100 clients that the firm could rely on for lead corporate work – thanks to Freshfields Bruckhaus Deringer's lead adviser role to Ferrovial. Not only does Herbert Smith not have a Spanish office to build links with the acquiring company, it is a jurisdiction that falls outside of the firm's European alliance.

Even more worrying are expectations that the Spanish will effect substantial changes to BAA's structure and management, effectively severing some of the firm's client links.

This would be less likely to affect Herbert Smith's property team, which has a long-term relationship with the client, but is more likely to hinder its main corporate relationships, which are conceded to be more narrowly concentrated with BAA's senior management.

Holding onto clients in such circumstances is not impossible. The BAA situation is similar to Slaughters' predicament in 2004 when Abbey was acquired by the Spanish CC client Santander. Back then, Slaughters insiders conceded they did not expect the firm to take future top-tier mandates for the bank. This month's instruction on its £3.6bn life assurance sale shows that it is possible ( see right). But the bid's result will sharpen minds as Herbert Smith gears up for a strategy review that is expected to focus on the thorny issue of the firm's cross-border strategy.

There will also be mixed feelings in the camp of Goldman Sachs' unsuccessful consortium, although in terms of fees lost it could be a lot worse. One adviser reports that lawyers are in line for a modest 20% discount on hours billed. Considering the inherent complications of a consortium-led debt finance bid, this makes for a substantial consolation prize. Ashurst put three of its most senior partners on the deal full-time, led by corporate head Adrian Clark, while all the advisers report that the demands of documentation were tough.

Ashurst will be pleased to have secured the lead counsel role to Goldman, notwithstanding the mass of conflicts the bid created. The deal also gave an early opportunity for ex-Allen & Overy heavyweight Tony Keal to stretch his legs at Simpson Thacher & Bartlett, with the New York firm appointed alongside Ashurst to handle acquisition finance.

Milbank Tweed Hadley & McCloy's London arm, meanwhile, bagged a bank-driven M&A role acting for the bid's debt providers. A case of better luck next time all round.