I’ve been standing shivering outside the birthplace of the modern City of London, when out of nowhere pops Peter Rees. We’d arranged to meet beneath the Gherkin in the heart of the Square Mile, the financial district that is the powerhouse of the UK economy. He’s like a tall Rob Brydon, all irrepressible Welsh charm and gushing enthusiasm for his specialist subject, the skyscrapers of the City.

For nearly 30 years, Rees was the man who ran planning here, overseeing the transformation of the area from a patchwork of fusty low-rise historical buildings into what is now a thrusting cluster of memorable high-rises: the Cheesegrater, the Walkie Talkie, the Can of Ham, 22 Bishopsgate (the tallest at 278m) and, of course, the mould-breaking Gherkin (the shortest, at 180m).

We have been taking a windswept walking tour of all the EC3 district’s notable high-rises, but now we retreat to the New Moon pub in nearby Leadenhall Market. Over pints of bitter, Rees regales me with tale after tale of his passion for the architecture of the City, how he loves the old as much as the new, how his favourite architect is not Richard Rogers or Norman Foster, but Nicholas Hawksmoor, whose apotheosis is the stout St Mary Woolnoth church overlooking Bank tube station, and how really good architecture is not just about creating something beautiful but a timeless mechanism to ensure a place serves its purpose well.