"It is the best festival in the world," he adds.

Like him, most concert-goers in the Gallery lean against the railing to see the stage, some with binoculars to follow the conductor close-up.

If it gets crowded, elbow room is at a premium in order to see the orchestra.

A few metres back from the railing, lying on a blanket, Erica Seo and her partner have made the opposite choice.

They listen to Robert Schumann's Violin Concerto with their eyes closed, each one lost in their own thoughts.

"It is just like being in the living room, but much better music, because it is obviously live, and you get really a feel of the detail, you can feel the pulse," she says.

Jane Smith, 61, is attracted by the "anything goes" ambiance.

Barefoot and swinging with the rhythm, she is a regular who comes several times a year－and always to the Gallery.

Standing by the access stairs, the ushers are relaxed toward Gallery-going Prommers.

Some groups of friends make a mini-picnic out of it, sitting on the floor munching sandwiches, with plastic glasses spread out around them.

The "unpretentious, relaxed" atmosphere pulls in a "much more diverse" crowd than other London classical music concerts, says Sarah Legrand, 33, who came with a friend.

"Here you can see students, young people with their kids," she says, looking around. "In other normal indoor classical music venues, most people are retired."

AGENCE FRANCE-PRESSE