Mountview Estates chairman Duncan Sinclair has pledged £10m worth of shares as security for his personal bank loan and overdraft.

The listed property company revealed today that Sinclair had pledged 400,000 shares, representing 10.3% of the company to Barclays Bank as security.

Sinclair follows other property company directors Aubrey Adams and Tim Ingram in disclosing the use of shares as security against personal loans.

Adams, the former chief executive of Savills, has pledged 10,000 shares, worth £45,000, in British Land, where he is a non-executive director.

Ingram, a non-executive director of Savills, has pledged 24,000 of the firm’s shares, worth £57,600.

Public company directors have pledged almost £700m worth of shares as collateral against personal loans.

More than 50 companies have disclosed share-backed loans in the two weeks since the City's top regulator declared an amnesty on such deals, which expires tomorrow.

The use of shares as collateral for personal loans without disclosing them sparked a row six weeks ago after David Ross, the co-founder of Carphone Warehouse, admitted that he had pledged almost 14% of the mobile phone retailer to JPMorgan as security on loans.

He was forced to resign from his directorships of Carphone Warehouse, National Express, the transport group, and Big Yellow, the self-storage company.