The Cambridge is a nineteenth-century pub on Cambridge Circus, Charing Cross Road. Built in 1887, it stands next to the Palace Theatre (formally the Royal English Opera House), which many Harry Potter fans will know is the theatre currently showing the Harry Potter and the Cursed Child play.
In The Silkworm, Strike decides to meet Robin at the Cambridge instead of The Tottenham so he can avoid future press incursions at his favourite pub (there had been a group of journalists on Denmark Street after Strike found Owen Quine’s body).
Shortly after Strike’s arrival, Robin gives him his birthday present: “a small basket covered in cellophane adorned with ribbon and containing Cornish food and drink: beer, cider, sweets and mustard. He felt ridiculously touched.”
Robin fetches Strike a pint of London Pride and a glass of wine for herself.
They discuss the Owen Quine case. Strike eats some of the chocolate from the basket, then orders steak and chips.
Before he leaves the pub, Strike also consumes apple crumble and three pints of beer. Sounds like a great birthday lunch to us. Have a great time here yourself by following Google Maps.