There's a wonderful documentary available in full on Youtube called "Michael Foot: Labour's Old Romantic" that I'd highly recommend for anyone interested. A wonderful, compassionate, fiercely intelligent man who was never leadership material, especially given his age at the time.
Yes, I've watched that. Very good indeed.
As of Foot, I deeply respect the man, despite certain areas of disagreements (mostly Europe). He was actually an effective politician, something that's frequently getting overlooked, quite skilfully managing the impossible as the Leader of the House in the Callaghan's government. But yes, as far as being leader of the party he was clearly past his prime.
And of course he was a formidable intelectual, retaining a sharp mind until his death.