St Matthew Passion, The Barbican (0171-638 8891) 6pm

"Mankind's darkest day" booms the Radio 3 trail. They are talking about today which, as all good Jews will tell you, is the much celebrated eve of Passover. Actually, Radio 3 is thinking Christian and talking about Good Friday. Now, call me a hairsplitter, but I thought Judgement Day was in the lead for darkest day, but never mind. In honour of the religious occasion, the station is broadcasting a performance of Bach's St John Passion, one of his two towering choral and devotional masterpieces drawn from the death of Christ. The Bach Passions are to Easter what The Messiah is to Christmas, and there are performances up and down the land, so even non-believers like me can surrender to their cumulative power. The Matthew Passion, in particular, needs no special pleading, but the chance to hear as fine a singer as Sarah Connolly singing the rapt alto solo "Erbarme dich" is enough to banish any lingering doubts.