Abstract The Law Commission has recommended reforming the approach to be taken where (i) a challenge is made in the English Courts to an arbitration award on grounds of lack of substantive jurisdiction and (ii) the challenging party has participated in the arbitration under protest. It has recommended including in the Act the power to make rules of court limiting both the grounds for such a challenge and the evidence that may be heard. The Law Commission’s proposed reform stems from concern that the present approach could be wasteful and unfair. This article seeks to explore whether the now extensive experience of challenges under section 67 of the Arbitration Act 1996 justifies those apprehensions.