Nils Pratley is right to deride the gold-plated design of HS2 (International investors are laughing at the HS2 shambles, 4 October). On BBC Radio 4’s Today programme in 2018, I questioned the decision to design for 400km/h running. HS2 had shown that increasing the design speed by 20% would save just four minutes from London to Birmingham, but increase energy costs by a quarter. HS2’s spokesperson simply replied “because we can”. This profligate approach is a travesty of engineering’s basic aim: to design cost-effective solutions to known problems. Fundamentally, the problems that HS2 was designed to solve are disparate. True, it will add to rail capacity. But a line with two terminal stations does not help connectivity. And HS2 was never, as claimed, an answer to our climate crisis. Early figures showed that the full network could take 84 years after opening to be carbon neutral. The most contested problem, though, is the regional divide. It is highly questionable whether a complete HS2 would have strengthened the economy of the north. Forty years of the TGV have not made France less Paris-centric. Wider regional benefits are achieved through “agglomeration” – the closer linking of economic centres within a city region. As your editorial (5 October) stated, investment should have started in the north. What the city region stretching from Liverpool to Sheffield and Hull desperately needs is better rail connections within it – a northern network. But Rishi Sunak’s Network North is neither a network nor wholly northern. It is simply a list of schemes that already had government approval. In the words of Rafael Behr’s lampoon of the Tory slogan (Opinion, 28 September), it’s a short-term tactic for a darker tomorrow. Tony May Emeritus professor of transport engineering, University of Leeds