In the richly diverse world of the London classical music scene can be found musical leviathans that rise up like surfacing whales, and much smaller musical events that dart just below the surface of the city in flashes of iridescent colour. I enjoyed examples of both last week when I attended a mammoth five-hour performance of Wagner's great opera Tristan And Isolde, and a cello recital given in a secret corner of an Inn of Court. The Wagner was a David Alden revival - part of the final season before the Coliseum is closed down for renovation. The opera began at five, the final curtain going down at 11pm with two intervals in between. Starting a major musical event at 5pm on a weekday in many cities would be a form of suicide - nobody would turn up. My opera companion rushed into the foyer along with another thousand or so people, five minutes before curtain up. Out of the late afternoon sunshine of workday London, we moved into the misty past of medieval Cornwall in western England. Just as the lights were going down my companion suddenly muttered, 'Oh no, it's the ENO - that means I won't understand a thing.' The English National Opera (ENO) has a policy of translating all librettos into English, so Tristan And Isolde would be singing to each other in English rather than German. My companion's wry comment was a reflection of the fact that the rival Royal Opera House sings in the original with surtitles so every word can be understood. Fortunately the singing was superb and the diction clear. The cast boasted some of the finest British singers with Susan Bullock as a transcendent Isolde and David Rendall as a fine Tristan, and conductor Dietfried Bernet did a wonderful job of drawing us into Wagner's cascading seductive harmonies. Act One ended in a thrilling blaze of orchestra and chorus. At the end of a long but transcendent evening we compared notes and discovered that we had both understood an impressive 40 per cent of what had been sung. As we strolled home we pondered on how we had both been dissolved in the sublimity of the music and singing and the way time is suspended by great art. The musical event I attended two nights later was tiny in comparison - a summer concert at The Chapel of Grey's Inn Court. This little chapel is hidden in the courtyard of one of London's four main Inns of Court surrounded by the chambers of some of London's top barristers. The recital by a top class soloist required no tickets and was free. I found myself sitting among a distinguished audience of about 40 barristers listening to Bach's sublime cello Suite No 3 in C major being played by world-famous cellist Raphael Wallfish. Late afternoon sunlight streamed through the stained glass window and I was as much in the presence of the sublime in this little chapel as I had been at the mighty opera house.