William Glock once claimed that Pierre Boulez could literally vomit at music he believed to be substandard. I wonder what he would have made of my friend, who fled at the interval of the opening concert of the Southbank festival on Friday blaming Boulez's Domaines for setting off a panic attack. Her physical response was certainly a welcome corrective to the nonchalance with which the critical world increasingly greets Boulez's language, many of whom still insist that the days of serialism provoking anger or revulsion are in the distant past. Boulez can still upset.

Earlier this year, conductor Manfred Honeck revealed to me his love of old vinyl: the crackle, the fizz, the lost musical traditions. His performances are marinated in this obsession. The idiosyncrasies of his interpretations hark back to a time when the rules were fewer and the colours brighter. Last night was no different. His Mahler Five steered clear of the sleep-inducing modern fixations with orchestral homogeneity and tastefulness and instead jumped right off the deep end.

Dominated by a focus on contemporary music, this year’s Proms’ Saturday Matinees have also developed something of a heavenward glance as the series has progressed. Last weekend it was the Christian mysticism of Hildegard of Bingen at the fore, with Britten’s Sacred and Profane providing a slippery foothold in the earthly. Yesterday we cast off worldly shackles entirely, gazing beyond the limits of our own humanity in the musical visions of Tippett, Tavener and Sofia Gubaidulina.

Sirs Harrison Birtwistle and Peter Maxwell Davies have now been at each others’ heels for almost 60 years. First, the composers were students together at the Royal Manchester College of Music. Then, once their careers began flourishing they kept rubbing against each other in concert programmes. Inevitable, really: the same organisations commissioned them; they were the Twin Peaks of British Modernism. Even now, for old times’ sake, the pair can’t escape each others’ shadow.

Forget almost everything you thought you knew about classical music. Forget the regulations and the rigmarole, the politeness and the prissiness. Forget the preening institutions. Forget the vocal doom-sayers. Classical music is in the throes of an extremely welcome revolution. The entrepreneurial spirit that seized and transformed British art in the 1980s is finally animating and unshackling this most stubborn of art forms. Operas are springing up in warehouses, concerts in bars.

One of the weirdest things about the Proms's "weird concerto" theme is that the concertos so far haven't been all that weird. Piano. Violin. Cello and violin. Cello, piano and violin. Pretty familiar stuff. Finally last night we got something bona fide off the wall: a concerto for string quartet from French rebel Pascal Dusapin. Was it weird enough?

Imagine you are at a study day being run by Friends of the Earth. They mount a play in which a group of angels who somehow got left out of the Book of Genesis fall to a completely barren earth, look around, and start reconstructing, re-enacting its life and death. They plant, grow, overgrow, eat, overeat; they tell themselves the earth will always be fruitful, but they’re mistaken. In the end two of the angels become Adam and Eve and walk off hand in hand into a ruined landscape lit by the rising sun. Then Luke Bedford sets it all to music.