The men were arrested on 23 July and later released on bail pending further inquiries. Hampstead police, in liaison with City of London detectives, are investigating the case.
According to one source: 'They are good forgeries. It is a professional job.' Royal Insurance yesterday issued a warning to stockbrokers via the Stock Exchange to be on the alert for forgeries.
It is also considering issuing a statement to reassure shareholders when it publishes its financial results next Thursday.
Its registrar, Lloyds Bank, is not certain how many of the forged certificates there are in circulation.
But it does not know of anyone who has been defrauded.Reuse content