Live broadcasts into cinemas have become something of a commonplace, and a welcome one: operas, theatre performances, even radio programmes. But a live broadcast into cinemas of the audience entering another cinema is a new one on me.

The idea is part of this year’s BFI London Film Festival, not as an avant-garde experiment but as a way of adding lustre to the closing-night gala: Saving Mr Banks, a sort of biopic of the film Mary Poppins with Emma Thompson as author P.L. Travers and Tom Hanks as Walt Disney (see image). We’re promised additional screenings of the film around the country, preceded by ‘live satellite footage from the red carpet’ — although at the time of writing the BFI website still advises those interested to ‘check back in late September’, so it might not be wise to hold your breath.

More reliably — though only in London — there will be 235 feature films and 134 shorts, presenting the usual dilemma of whether to go for something relatively sure-fire that seems likely to be back in a few months, or something chancier that might never return. Things that weren’t fully sold out yet in the first category include a Jonathan Glazer ‘kitchen-sink sci-fi’ with Scarlett Johansson as a killer alien (Under the Skin, 14 October). In the second category, I’m tempted by a 13-year-old autistic boy’s ‘poetic odyssey’ on the New York Subway (Stand Clear of the Closing Doors, 11 October). But they may be gone by now, and there’s an awful lot more. You’ll have to check back on that website: lff.org.uk.