The Magnum Concilium, or Great Council, was established in the reign of the Normans. It was convened at certain times of the year when church leaders and wealthy landowners were invited to discuss the affairs of the country with the king. It was called for the last time in 1640 (after a lapse of centuries) when King Charles I was defeated by the Scots. Since then it has had no role, lawmaking or otherwise.
In ancient times the king would call the Great Council and the King's Court (Curia Regis), who were semi-professional advisors who would stay behind until the work was done. The latter grew into the Parliament (concilium regis in parliamento) and, especially as it split into the House of Lords and House of Commons, thereby assumed the participation of the nobility.
In 2008 The Lord Glanusk suggested that the time had come for a recall of the Magnum Concilium, since hereditary peers had lost their right to sit in the House of Lords under the House of Lords Act 1999.