Exodus of big clients, falling profits and dire forecasts raise prospect of a once ‘unthinkable’ breakup

A dark joke is doing the rounds in adland that the original Wire and Plastic Products, the small Kent-based basketmaker that Martin Sorrell bought 40 years ago as a stock market-listed vehicle to build WPP, might outlast the advertising giant itself. Now named Delfinware, and a maker of dish drainers with 10 employees, the business is 56 years old and privately held, while the listed global ads group that was once its parent struggles amid a changing corporate landscape.

For decades the financial success and dominance of WPP – its 100,000 employees service global clients from Ford to Coca-Cola – has been the corporate manifestation of Britain’s shining reputation for creative advertising.