A study by Labour Research into the 1995 Masonic Year Book - the Who's Who of Freemasonry - also shows that nine Tory peers occupy senior posts in the secretive order.
The Commons Home Affairs Select Committee is due to break new ground by holding the first parliamentary inquiry into the extent of Masonic influence on the police and judiciary early next year.
The study also provides food for thought for Lord Nolan and his committee on standards in public life, which has also indicated a willingness to look into the mysterious craft.
As a law lord, Lord Nolan may find himself investigating his colleagues: 32 judges or retired judges are listed in the Masonic Year Book.
According to the book, the House of Lords has more leading Masons than the Commons. They start with the most powerful of all, the Duke of Kent, who, as is well-known, is grand master of the United Grand Lodge of England, the order's governing body in this country.
The number two Mason is Lord Farnham, an Irish peer. Earlier this year, the Irish peers lost their long campaign to be allowed to take their places in the Lords so he does not count among the 25 top Masons in the upper house.
Of those 25, nine are Tories, 11 are crossbenchers and four do not declare any party allegiance. One, the Duke of Kent, is above party politics as a member of the Royal Family. The Tory peers include: Lord Belstead, a former leader of the House of Lords; Lord Lane of Horsell, a former chair of the National Union of Conservative Associations; and the Earl of Elgin & Kincardine. Lord Belstead was president of the board of general purposes of the United Grand Lodge in 1994-95, while the Earl of Elgin & Kincardine is an ex-grand master for Scotland.
Four sitting Conservative MPs appear in the handbook: Tony Baldry, a junior minister; Sir Gerard Vaughan; Sir Peter Emery and Ian Bruce. Of these, Mr Bruce, who sits on a number of United Grand Lodge committees, appears to be the most prominent.
Former MPs, all Tories, in the book are: Sir Neil Thorne, who loaned his Westminster home for the Prime Minister's leadership campaign headquarters in the summer; Sir Ian Percival, a former solicitor-general; Sir David Trippier; Sir John Wells and Sir Edwin Leather. One Conservative former MEP, Sir Peter Vanneck, is also listed.
Only one former Labour politician is in the book: Niall Macdermot, who retired as Derby North's MP in 1970.
As well as Tories and judges, businessmen also occupy senior posts "on the square". They include Sir John Banham, former director-general of the CBI and a director of National Westminster Bank and National Power.
Sir Gerrard Peat, a partner in KPMG Peat Marwick, the leading accountancy firm, is a top Mason. He is also a past auditor to the Queen's Privy Purse and treasurer of the Association of Conservative Clubs.