Michael Spencer, founder of inter-dealer broker Icap and Conservative party co-treasurer, has sold his stake in Numis, which was part of a package of shares pledged against loans to his private company, and stepped down as chairman of the City broker.

His 12 per cent holding in Numis was included along with the bulk of his Icap stake in the parcel of securities used as collateral for a loan from HSBC to the Intercapital Private Group Limited, an investment vehicle in which Mr Spencer, his estranged wife and his children’s trusts own a 55.1 per cent stake.