Because voters' names have to be on the lease of a property in the City, law firms and some accountancy firms which list every partner on the lease have a much larger proportion of the vote than any other sector of the electorate.
But under reforms partly forced by the Government, the corporation is now planning to allow limited companies to vote which, if approved, would expand the electorate from 20,000 to 50,000 when the reforms come into force by an act of Parliament in the 1998-99 session.
Solicitors account for between 3,000 and 3,500 of the electorate, so their share of the vote would be diluted from around 17 per cent to seven.
Cassidy, senior partner at City firm Maxwell Batley, said: "The solicitor vote will be totally swamped. This can only be a good thing. It's totally unfair that solicitors' firms can dominate particular wards."
Linklaters partner Jeffrey Bailey, for example, almost certainly was helped to his Cripplegate seat from the vote of some of his 180-odd partners whose office is in the ward.
Clyde & Co shipping partner Clive Thorp, a council member for Billingsgate who admits he won his seat in the 130-electorate ward by getting many of his 80 partners out, thinks the reforms do not go far enough.
Large companies such as NatWest may still get only a handful of votes and he thinks there are too many council members in each ward.
"Why do we need four council members in Billingsgate?" he asked. "It's just history. It's also very embarrassing for me to be in a position where I can get my partners to vote me in."
However, he was not sure that the vote should be opened to all commuters to the City as some have suggested. He stressed that council members do not align themselves with political parties. They are not paid and do not get expenses.
"They are people who want to give something back," he said. "It would be a shame if that were to change."
Current chair of the policy and resources committee Judith Mayhew, a partner at Wilde Sapte, said law firms dominate in some wards while accountancy firms dominate in others.
The number of votes allocated to limited companies had not yet been decided, she said, but it would be based on a sliding scale depending on the business rates the company pays. The corporation is 99 per cent funded by business rates.
Cassidy pointed out that although many solicitors played an important role in the corporation, it was not always easy to get their partners voting. He said there were some partners at Slaughter and May who run a mile whenever asked to vote.