Former Commons speaker Baroness Betty Boothroyd vowed that she would never again wear ermine as she launched an attack on the "medieval trappings" of the House of Lords.
She said the time had come for lasting reforms of the Upper House which blended with traditions and the needs of parliament as a whole.
In written evidence to the Parliamentary Public Administration and Constitutional Affairs Committee, Lady Boothroyd called for:
:: A reduction in the number of peers in the Lords to a maximum of 450;
:: Curbs on the prime minister of the day awarding unlimited peerages for political services;
:: Members retiring at the end of the parliament when they reach 80.
The retirement of peers who seldom come and contribute little would further cut the size of the Lords.
She pledged: "For my part, I shall not wear ermine again. The House of Lords does itself a disservice in clinging to medieval trappings.
"The splendour of the Queen's presence at state openings is sufficient reminder that we are a parliamentary democracy and a constitutional monarchy."
Lady Boothroyd added: "The unfettered power of patronage enjoyed by successive prime ministers has exposed Parliament to unfair scorn and ridicule.
"Our democracy is undermined by it. Historic Lords reform lies within our grasp provided the next steps are not too steep and Parliament asserts its rights."
She went on: "I believe the House of Lords could work a lot better. Its 800-plus membership makes it almost unmanageable, hinders the business of the House and needs urgently to be reduced.
"I favour a reformed House of between 400 and a maximum of 450.
"But I would be loath to see the number of independent crossbenchers - I declare a personal interest as one of them - sharply reduced.
"Whatever the figure, it should be capped below the size of the House of Commons after the next election."
She spoke of the need for the limitation of the prime minister's unfettered use of the royal prerogative, saying: "Downing Street's role as the unaccountable dispenser of privilege is no longer acceptable."
Lady Boothroyd said: "Phasing out the remaining hereditary peers would create even more headroom, beginning with the abolition of their bizarre by-elections to fill vacancies that arise from natural causes."
She said future prime ministers would still have the right to appoint peers to sit on the government's front bench in the Lords but all political nominations for the peerage would face in-depth, independent scrutiny by a statutory Lords Appointments Committee.
Lady Boothroyd said these reforms meant the Lords would be leaner, younger and more rigorously vetted and would guarantee the supremacy of the Commons.