EY has hired Big Four rival PwC's head of financial services regulation Martin Sandler, as the heavyweight accountants continue headcount growth.

Sandler will join EY next week as a partner in the UK financial services law team, after nearly two years at PwC. 

He joined the accountant in 2016 after it integrated its legal arm into its main business, having previously been a partner at legacy Berwin Leighton Paisner and Bird & Bird. Sandler also spent 10 years at Bank of America Merrill Lynch, where he was head of EMEA equity counsel.

EY's head of law for financial services in the UK, Matthew Kellett, said: "Martin brings the deep knowledge and understanding of operating within a Big Four firm, in addition to the invaluable experience of having worked on the client side in financial services for more than a decade.

"This combination of experience will be a real asset as we continue to strengthen our financial services legal practice in the UK."

The hire comes amid a fierce ramp-up of the Big Four's legal propositions. Since launching its legal arm in 2015, EY has grown its team to about 200 people in the UK. Globally, EY has more than 2,200 law practitioners in EY member firms across 83 jurisdictions.

KPMG has also recently ramped up its legal offering, launching a legal consultancy business in the UK and recently expressing ambitions of doubling its legal offering.   

Deloitte, meanwhile, hired heavyweight Allen & Overy partner Michael Castle earlier this year to lead its UK legal arm.