This, from The Guardian, this morning:

London’s Mayor, Boris Johnson, has paid tribute to his deputy after he died in hospital.

Sir Simon Milton, who was deputy mayor for policy and planning and was also Johnson’s chief of staff, was described by him as “a wonderful colleague” who brought “calm, logic and warmth” to the role.

via Sir Simon Milton, Boris Johnson’s chief of staff, dies aged 49 | UK news | The Guardian.