There is something awfully rotten in the British construction industry.
Everything is far more expensive than elsewhere on the continent.
HS2 somehow manages to cost more per mile than an underground railway in some parts of the world!
There is a lot of research into why costs are higher in the UK. This Treasury report is just one
https://assets.publishing.service.g...t_data/file/192588/cost_review_main211210.pdf.
Main reasons quoted are
our stop-start process of construction ie no guaranteed long term pipeline
Projects started before design is sufficiently complete.
Use of quoted budgets rather than aiming at lowest cost
Over-specification and use of bespoke solutions when off-the-shelf designs would suffice;
public sector to risk averse
to fragmented a sector with overuse of subcontractors
lack of investment to improve productivity.
The other factor is higher land values.