Herbert Smith Freehills (HSF) finance partner Jason Fox has quit the firm to join the London arm of Houston's Bracewell & Giuliani.

Fox, who previously headed legacy Herbert Smith's finance practice for five years until 2010 and has a particular focus on the energy sector, will join Bracewell as senior partner of the London office. His start date is set to be confirmed in the next few days.

fox-jason-herbert-smithFox's hire comes after Bracewell boosted its London base in January this year with the hire of Simmons & Simmons energy partner Julian Nichol as London managing partner and HSF senior associate Alastair Young as a partner.

Before Nichol joined, the US firm's City arm was led by partner Adam Mozel, with partners John Brantley, Christopher Williams, Michael Kuhn and chairman Patrick Oxford splitting their time between the City and Bracewell's Houston and Dubai offices.

Fox will help to build out the London office, with Nichol confirming that more hires at associate and partner level are planned for later this year.

"What we are doing in London is setting up in the energy space, which is the core strength of the firm," said Nichol.

While at HSF, major roles for Fox included advising a syndicate of 25 banks headed by HSBC and BNP Paribas on a $2.5bn (£1.65bn) reserve based financing for Lundin Petroleum, and an advisory role for BNP Paribas and IFC on a $200m (£132m) borrowing base facility for Salamander Energy.

Meanwhile, at Simmons, Nichol worked on project development and financings and M&A in the power, oil and gas and mining sectors, with a particular focus on Africa and Middle East. Young's work at Herbert Smith focused on cross-border oil and gas M&A, as well as joint ventures, project development and regulatory matters.

Bracewell, which has former New York mayor Rudolph Giuliani (pictured) as a name partner, has more than 470 lawyers across 10 offices in the US, London and Dubai. Bracewell's City office is particularly active for clients in the energy sector.