Firstly, Foot should never have become leader, simply because he was unsuited to the role and this was obvious beforehand. The dilemma in 1980 was that Healey “never stood a chance” as Richards suggests. Therefore, Foot has pressurised into standing because there was no alternative. Also some Labour MPs wanted Foot, making it easier to justify the SDP.
Secondly, and this is the crucial point that Oliver Kamm has missed, it was the deputy leadership election in 1981 that was the watershed moment. John Rentoul, as usual, is spot on:
The actual choice facing the Labour Party in this period was between Footism and Bennism, and by choosing Foot, in the form of Healey as deputy leader, over Benn, in 1981, the party chose to survive.
And that is why, comrades, it was Denis Healey who saved the Labour party.