Parliament Choir/Southbank Sinfonia, Westminster Cathedral, London

A senior frontbench Liberal spokesman (tenor); a Rural Affairs minister at odds with the foxhunting lobby (tenor); a Tory ex-minister with a rural constituency and diametrically opposite view (baritone); plus a similarly deep-throated basso colleague. No Greens or UKIP - yet.

Welcome to the Parliament Choir. Once again, the Lords don't have it: only 10 of them joined the warblers, including three baronesses (notably, the choir's rich-toned Liberal, Baroness Walmsley), while 14 members of the Commons fill up the ranks (including The Five Tenors). Secretaries, cooks and cleaners boost numbers to nearly 100. All laudably democratic.

Simon Over, one of London's most enterprising conductors - and a leading lieder accompanist to boot - founded the Parliament Choir, together with his fledgling Southbank Sinfonia, when he shed being organist at St Margaret's, Westminster: a role once held - auspiciously - by Richard Hickox. The BT-backed choir launched with a millennial bash - a Handel's Messiah in December 2000, for which MPs invited constituents to join their mellifluous ranks. A Nelson Mass and Elijah are in prospect. And for Verdi's Requiem, these Palace of Westminster Pavarottis swelled themselves to huge numbers by recruiting back-up from choirs as diverse as Bath, Croydon, Sussex, Lewisham, and the St Michael's Singers from Over's home town of Coventry. Even the Treasury Singers were there - Gordon, seemingly, was otherwise occupied.

This was fabulous singing by any standards, from the first perfectly defined, heads-up "et lux perpetua". Was there a department of chorus and youthful orchestra that didn't deliver? No, it was all there - those subtle brushings of comic bassoon and clarinet where the Verdi of Otello and Falstaff offsets tragedy with unalloyed genius. All except the awful fugal "Libera me", which sets the words like jingoistic rubbish.

By then, the soprano Judith Howarth had made amends for her amateurish, swooping portamenti elsewhere, delivering her fabulous apotheosis: one of the best moments. Deservedly upstaging her was the beautiful singing of the mezzo Wendy Dawn Thompson (what a find); the splendid Jeremy White (shades of John Tomlinson, but controlled); and the Italianate tenor Rafael Vazquez - a notable discovery.

Only a rocky Offertorium launch (cellos) rocked the boat: all else was tip-top. You could feel the audience respond, sense the intakes of breath: a truly magnificent, spiritual experience.