Chris

Principally the cost - an effective Parliament for England, governing 40 million (?) people, would be a vastly expensive business. Then there's the question of the calibre of those elcted to it. Both the Welsh Assembly and Scottish Parliament have suffered from being populated largely by ambitious former district councillors (this is particularly so in Wales). Fact is, the most able politicians are at Westminster.

Another big problem is the fact that the Welsh Assembly is not a Parliament. It can't pass Primary Legislation, it can only make secondary orders based on legislation already passed in London. So any legislating Parliament for England would also have to perform the same function for Wales. This would both defeat the object of having an English Parliament and enrage the Plaidos in Wales, who don't like being reminded that Wales historically has no official identity separate from England. The Welsh Assembly is really just a jumped up county council (there are only 3 million people in Wales) and is thoroughly ill-qualified to become a Parliament itself.

A better solution might be to reclaim the Wesminster Parliament as ours and set up a new UK Parliament, attended by delegates from Wales, Scotland, England and Northern Ireland, which would convene only when whole-UK matters are under discussion.