A trip to the restaurant that sits atop the No. 1 Poultry office block in London’s financial district is a chance to experience firsthand the "Tale of Two Cities" that’s upending the commercial real-estate market.

From the vantage point of the Coq d’Argent you can gaze out at a forest of new skyscrapers developers hope will bring in big rents and even bigger prices. For the South Korean owners of the older WeWork-occupied building down below, the future looks far bleaker.

Taking in the view, Kaela Fenn Smith — ex-executive at property giant Land Securities, and now managing director of CBRE Group’s environmental, social and governance consultancy — speaks of the "huge flight to quality” transforming the office market, where only "the truly grade-A space” will do. Her comments come as flawless environmental credentials become a must for corporate renters, many of whom are thinking about downsizing because of the work-from-home revolution.