Why Britain would probably not buy the M10 Booker

Would the British Army be interested in buying the M10 light tank?

Interested, yes; likely to buy it, no. Limited money would be better spent on the main-tank fleet than on another small logistics chain.

The British Army would find the M10's capability useful, but force scale creates an objection: a small army cannot efficiently support every specialized platform it might want. Each additional fleet creates its own maintenance, training, parts, and logistics demands. If money became available for more armor, the recommendation is to prioritize additional Challenger tanks or their replacements instead of adding another small vehicle type.