Yoko Ono Plastic Ono Band, Royal Festival Hall, London

She may claim to revel in the role of outsider, but on this showing Yoko Ono has as much need of love as the rest of us. In the past, Ono has said that she thrives on brickbats, yet tonight, as part of the Ornette Coleman-curated Meltdown Festival, this spry 76-year-old admits some trepidation to a huge round of applause.

This despite the accolades she has already received this month: a Golden Lion for lifetime achievement at the Venice Biennale, plus a similar award from Mojo magazine. That latter is particularly symbolic of an admission that she was not necessarily responsible for the break up of her husband's band.

It is easy to forget that Ono was wailing into a microphone before Brian Epstein signed The Beatles. Then again, much recent work has been achieved by remixers, most successfully on 2007's Yes, I'm a Witch album. Now her son Sean Lennon has resurrected the Plastic Ono Band, the amorphous group that worked with both her and John, from his own contacts book.

This new generation's sound predates the original's cavernous garage racket, as they hark back to Sixties psychedelic jams. The occasional appearance of Mark Ronson on bass gives an even more retro feel. Never work with children and animals? Never share the same stage as parents, more like, as Ono reminisces that he and Sean were "beautiful babies", even if the latter became an "arrogant 17-year-old". Much of the time, such banter is sweet relief from Ono's incessant caterwauling.

It is a thing to behold in small doses, as Ono moves from low-end moan to high-pitch ululation. This drags on in her more freeform numbers, while atonal attempts at singing often get lost in Sean's hard-rocking fug. Among occasional moments of clarity, the elegantly straightforward "I'm Going Away Smiling" comes with bewitching support from Antony Hegarty.

"Kurushi", which Ono sings in her native Japanese, is affecting. Inspired by a shrine in Hiroshima, its title means one can not breathe. Sean, meanwhile, as musical director, plays piano like a timid cabaret entertainer. These are rare departures for a band eager to fill any spaces.

The Plastic Ono Band close with "The Sun Is Down", which mixes The Orb's dubtastic house with a hippy-dippy freak out – a welcome departure for its creator, who dances merrily, cheered, it seems, by her belated acceptance.