Simmons & Simmons and Fieldfisher have picked up new partners from Baker Botts as the US firm's London arm has seen a number of senior exits in recent weeks. 

Intellectual property partner Mark Heaney left the firm on Friday to join Simmons & Simmons. His practice has a particular focus on patents, confidential information, and copyright and related rights and he will join Simmons on 14 October.

Project finance special counsel Matt Hinxman joined Fieldfisher as a partner on Friday.

Both exits follow the resignation of the former partner in charge of the London office, Steve Wardlaw, who left in April to pursue a career outside the law. 

A source close to the firm blamed the exits on low morale, with further exits rumoured to be likely. 

IP partner Heaney only joined Baker Botts in January 2015 from Bird & Bird where he was a partner.

According to its website, Baker Botts now has 12 partners and 21 other lawyers in its London office.

A firm spokesperson said: "Steve Wardlaw retired from the firm in April to pursue business interests outside the practice of law. He is now executive chairman of Emerald Life. The movement of lawyers from one firm to another is a regular occurrence. In fact we have several new lawyers joining over the coming weeks.

"Matt Hinxman was a special counsel at Baker Botts and recently left to pursue a partnership opportunity at another firm. Mark Heaney joined Baker Botts from his prior firm with very onerous restrictive covenants, and has now chosen to move to another firm."

In January Baker Botts closed its Abu Dhabi office, relocating its personnel in the region to Riyadh and Dubai.

The oil and gas-focused firm posted 2014 revenue of $653m (£429m), up from $586m (£382m) in 2013. Its revenue per lawyer increased by 10% to $942,000 (£619,000), up from $860,000 (£561,000) in 2013. Profit per partner was $1.7m (£1.1m), up from $1.36m the year before.