SCOTTISH MPs could hold England to ransom if English Votes for English Laws (Evel) was not implemented, William Hague has insisted.

In a keynote speech given in central London under the slogan "A Fair United Kingdom", the Commons Leader set out the Tories' preferred option for answering the historical West Lothian Question.

Mr Hague stressed that, in light of more powers being transferred to Holyrood, it was not sustainable for Scottish MPs to have, potentially, a deciding say on laws or parts of laws that only affected England, including those on the Budget and welfare.

The Yorkshire MP made clear this was not about any part of the UK gaining rights or advantage at the expense of any other part but about providing fairness in the constitution and changing the way Britain was governed for the better.

Under the Hague proposal, all MPs would be involved in the first main Commons debate but that at the detailed committee stage only English MPs would have a say. The Report Stage when proposed detailed amendments are further considered would also involve all MPs.

To underline the fact that no England-only legislation could pass without the full consent of English MPs, a new legislative stage is being proposed - an English Grand Committee, made up of just English MPs, who would have to pass a Legislative Consent Motion.

If this were not passed, then a Bill could not proceed to its final stage, Third Reading; it could go back for further consideration. If it were passed, then all MPs would vote on the final make-up of the proposed Bill.

In practical terms, this means that at the Grand Committee Stage English MPs could veto anything they did not like but, also, at Third Reading, all MPs, including Scots, would have the potential to block a Bill wholesale.

Mr Hague said, in light of enhanced devolution to Scotland, the current constitutional framework was "manifestly unfair" to England.

"If we do nothing about this, the next time Scottish MPs cast decisive votes on matters that affect only England, there will be a very strong reaction to it. It is better to create a fair and sustainable system now as part of the current wave of constitutional change," he argued.

The Tory frontbencher berated Labour for not wanting to answer the West Lothian Question, saying they refused to do so because Ed Miliband wanted to keep open the option of a future Labour government being propped up by the SNP.

"So if Evel is not implemented, there is the real prospect of England being held to ransom by the demands of the SNP or Scottish Labour MPs," declared Mr Hague.

"It will not be English MPs deciding what happens to schools and hospitals in England but Ed Miliband and Alex Salmond, acting out of their own political self-interest rather than what is best for England and the United Kingdom."

But Labour branded the Hague proposal an "absolute shambles".

Ian Murray, the Shadow Business Minister, insisted the right way forward was Labour's proposal for consideration through "a people's convention and not by politicians in back-room deals for their own political benefit".

As Ukip denounced the Tory plan as chaotic, the Liberal Democrats also warned that it would be a "major mistake" to "rush through" radical changes without a constitutional convention.

Meantime, the Conservative Right was also uneasy. Tory backbencher Bernard Jenkin said it was "not really English votes for English laws" as it "invites the SNP to come in and interfere with English laws and that might prove to be counter-productive; we will have to wait and see".

Elsewhere, Stewart Hosie for the Nationalists added: "It is ridiculous that the Tories continue to push the shambolic and confused plan to stop Scottish MPs voting on parts of the entire UK budget."