The firm has also faced criticism for leaks last year at its Alaskan operations, delays on starting up some key projects also affected BP's performance, eroding Lord Browne's wages as a result of a drop in share prices.

BBC: NEWS | Business | BP chief Lord Browne's pay falls

Speaking last week on RTE, Ireland's national broadcaster, Browne was asked if O'Sullivan's four-year deal would be honoured.

BBC: O'Sullivan's future 'threatened'

But new children's laureate Anthony Browne has said writers should not be exempt.

BBC: School safety 'insult' to Pullman