The UKs last big road building splurge was in the 90s and hit major resistance from environmentalists etc. So that build out never really finished. Plus geograp

The UKs last big road building splurge was in the 90s and hit major resistance from environmentalists etc. So that build out never really finished. Plus geographically the UK is quite concentrated down in the south east. So you don't need vast lengths of motorway to reach the extremities. I'm less knowledgeable about Spain, but I know they've had a massive building boom in the early 2000s, was it part of that? Plus you have populations on all 4 sides of the Iberian 'square', so you do have to build long roads to connect them all.