Madrid Terminal 4 cost about half what Heathrow Terminal 5 did. Same architect. Both billion € projects. Both complicated sites next working airports. Similar s

Madrid Terminal 4 cost about half what Heathrow Terminal 5 did. Same architect. Both billion € projects. Both complicated sites next working airports. Similar sizes and infrastructure. Madrid T4 was a public project and Heathrow T5 was a private project. So I think it's more to do with the contracting culture of a country than wether it's a private or a public project. With the UK megaprojects there's about 5-10 project manager guys who rotate between them. It's quite a small group of people who all know each other. A lot of the people working on HS2 now would have been junior project mangers on Heathrow T5 or Crossrail in the past; they bring the culture with them between projects. I think UK construction culture is quite slow and bureaucratic compared to say France or Spain, but not as bad as the US which is on another level.