As i believe think that why should a Scottish MP be allowed to vote on a matter that only affects England but wre can't vote on matters that affect Scotland, as if they vote a particular way in a bill then that could cause the bill to be passed even though the vast majority of English MP's opposing the Bill.
Finally doing something about the West Lothian Question, where a Scottish MP is allowed to vote on matters that only affect England but the same Scottish MP is not allowed to vote on matter concerning his own consituency e.g a Member of Parliament for West Lothian being able to vote on matters affecting the English town of Blackburn, Lancashire but not Blackburn, West Lothian in his own constituency.
Another example being English students are required to pay top-up tuition fees, while Scottish students are not. The legislation imposing top-up fees on English students passed by a small majority of 316 to 311. At the time opposition education secretary Tim Yeo argued that this low majority indicated that the passing of the law had hinged on Scottish MPs voting to introduce tuition fees that the Scottish students would not have to pay.