asked the Minister of Fuel and Power how many grades of coal are recognised by his Department; and on what criteria grading is determined.

Seven, for house coal. The main criteria are size, ash content, rate of burning and calorific value.

Is the category of any coal at any given colliery determined by a committee, or how exactly is it arranged?

It is determined by the Coal Board, in consultation with the merchants, with whom they have special arrangements.