“I don’t want to talk, I want to communicate with this,” says Mihhail Gerts at one point during his 15 minutes with the Guildhall orchestra, waving his baton.

Words that orchestral musicians are always glad to hear (and a reason why conducting students tend to have it drummed into them to keep rehearsals moving), but today there’s another reason to keep words to a minimum.

It’s a cold, bright December morning here in London and we’re in the music hall at the Guildhall School of Music and Drama preparing for the 2014 Donatella Flick LSO Conducting Competition. There’s an orchestra warming up and groups of people standing around, also warming up (I did say it was cold).

‘Just play what you see,’ said Lennox Mackenzie to the orchestra before the competition proper began.

They did just that at the opening of Mozart 39, one of those slow introductions that a conductor has to decide whether to conduct using four slow beats to a bar or eight faster ones. Most importantly of all, they need to tell the orchestra which they decide on! If it’s not clear, some players will see one, some the other and you can imagine the noise that results.

On Thursday 11 December, film composer Alexandre Desplat joins the LSO to conduct us through a selection of some of his most iconic scores, including The King's Speech, Harry Potter and the Deathly Hallows, The Grand Budapest Hotel and more.