London’s stock market could be about to lose one of its biggest companies — a blow not only to the City, but also to concerned investors who believe it could spark one of the biggest investment calls funds will have to make this year.

BHP, one of the largest constituents of the FTSE 100, announced plans on 17 August to ditch the London Stock Exchange as the primary location for the listing of its shares, opting for Sydney instead, where its parent company is based.