One of the most valuable accountancy jobs in Britain is changing hands after BP chose Deloitte to carry out its audits from 2018.

BP invited new auditors to pitch for the work earlier this year in order to meet a new rule forcing large companies to change auditor at least once every 20 years.

EY, which has held the contract for several decades, is thought to be the only one of the big four accountancy firms that did not pitch for the work.

BP’s audit contract is one of the most lucrative among Britain’s blue-chip companies. EY earned $51m (£41m) for its work with BP last year, comprising $47m for its audit services and $3m for other work such as tax advice.