Should the merger go through, the new firm – which would be called BDO – would still only be around a quarter of the size of KPMG, the smallest Big 4 firm. Its revenues will be around £560 million ($720 million) and it would employ 264 partners and around 5,000 staff.

Paul Eagland, BDO’s UK managing partner, cited growth opportunities, better service to clients, Brexit resilience and similar working cultures as the main reasons for the merger.

He also cited discussions around audit reform – which BDO has supported strongly – as having increased companies’ awareness of BDO’s services, and said the merger is part of its effort to compete in the higher reaches of the audit market.

BDO merged with Grant Thornton South Africa earlier this year.