The word ‘discovers’ covers not only the case where the Inspector finds out new facts but can have a wider meaning. Cenlon Finance Co Ltd v Ellwood 40 TC 176
A change of opinion to the law, by an Inspector, is a discovery which justifies additional assessment. W Ltd v Wilson 1974 II ITR 627
In Hammond Lane Metal Co Ltd v O’Culachain 1989 IV ITR 197 the court held that the unappealled assessment and the compromised appeal have the same force and effect. Therefore if the unappealled assessment can be the subject matter of a discovery under section 924 so can the compromised appeal.