On a hot summer’s evening on London’s busy Oxford Street, a crowd of fashion influencers, models, journalists and the odd City analyst gathered for a first look at the upmarket revamp of Marks & Spencer’s landmark Pantheon store.

Some may have had to double-check they had the right address, such is the scale of the makeover at the 88-year-old outlet, which is intended as a blueprint for change across the retailer’s more than 200 large stores.