When Harvard discovered that students outside Cambridge, Massachusetts, could access these lectures, the administration asked Miller to give up the course.

CNN: Do virtual classrooms make the grade?

Sir Christopher has said without "clawback" of profits it would be difficult to justify making transitional payments and said it could be enforced by making any further payments "conditional" on MPs agreeing to give up profits when they sell the property.

BBC: MPs' second home profits 'should be surrendered'