Whitbread enjoyed its best day of trading in 2017 after break-up speculation was reignited by activist investor Sachem Head Capital taking out a stake in the Costa Coffee and Premier Inn owner. Whitbread revealed in a regulatory filing that the fund – which is headed by Bill Ackman protégé Scott Ferguson – has taken out a 3.4pc stake in the company through contracts for difference. Analysts have recently noted that Whitbread’s weakness leaves it susceptible to interest from activist investors and private equity, with its shares slipping to an 11-month low in November.