The Sewel Convention House of Lords Debates 21 July 1998 c. 791
Clause 27 [of the bill; s.28 of the Act] makes it clear that the devolution of legislative competence to the Scottish parliament does not affect the ability of Westminster to legislate for Scotland even in relation to devolved matters. Indeed, as paragraph 4.4 of the White Paper explained, we envisage that there could be instances where it would be more convenient for legislation on devolved matters to be passed by the United Kingdom Parliament. However, as happened in Northern Ireland earlier in the century, we would expect a convention to be established that Westminster would not normally legislate with regard to devolved matters in Scotland without the consent of the Scottish parliament.If problems do arise the solution is for the Scottish executive and the United Kingdom Government to resolve the matter through political dialogue. That is what differences between mature parliaments and executives will be concerned with. That is what happens in other political systems. I cannot believe that it is beyond our wit to develop such a convention. That is much more suitable than through the business of legislative ping-pong or tennis. If this Parliament thought the situation had got to a stage of total impasse, it would be possible to look again at the Bill and enact primary legislation affecting the reserved matters. That is the ultimate route. There should be mature political dialogue to resolve a difference, which is better than legislative tennis. If an impasse results there is the ultimate fallback position of looking at Schedule 5 and changing the devolved powers.