On the bank holiday weekend, the political satirist Armando Iannucci was driving along the M40 to spend a couple of days in Snowdonia and stopped off at a Starbucks on the way. As he is a man who likes to record all his thoughts on Twitter, he dispatched this message to his 80,000 followers: “Still surprised that, despite their market dominance, Starbucks haven’t eliminated the slight smell of lavatory you get as you enter.”

Within minutes, Darcy Willson-Rymer, the UK head of Starbucks, had replied: “Thanks for your feedback. Which store did you visit?”

Mr Iannucci confirmed that he was at the Warwick services but that the pong was in several stores. The managing director thanked him again and promised to investigate. The satirist then tweeted: “Good news. Starbucks are now looking into their pervasive lavatory smell.”