The police investigation into veteran singer Sir Cliff Richard has "increased significantly in size" since its inception and involves "more than one allegation".
South Yorkshire's Chief Constable David Crompton says the expanding nature of the investigation meant he could not give a date when it would be concluded.
In a letter to Keith Vaz, chairman of the Commons Home Affairs Select Committee, Mr Crompton said the force was in regular contact with Sir Cliff's lawyers.
