THE imposition of a £10 fine for violating a no-smoking ban on a train to Brighton is an unlikely start for a decision of major constitutional importance–even when the incendiary incident occurred, as here, on 5 November. Nevertheless, Boddington v. British Transport Police [1998] 2 W.L.R. 639 has provided the House of Lords with the opportunity to deliver a strong affirmation of a defendant's right to raise the validity of the administrative action which has resulted in his prosecution as a defence in criminal proceedings.