Shares in Whitbread soared almost 7% after it emerged that an activist investor has built a stake to become the largest shareholder in the company.
Elliott Advisors confirmed at the weekend that it now holds a stake of more than 6% in Whitbread.
According to reports, Elliott Advisors wants Whitbread to be split into its Costa Coffee chain and its Premier Inn business.
A spokeswoman for Whitbread declined to comment.
Whitbread's shares were up 6.8% at midday to £42.04.