GORDON Brown, in what could be his final House of Commons appearance, will next week launch a direct attack on David Cameron's desire to ban Scottish MPs from Westminster debates and votes.

The former Prime Minister, who played a pivotal role in the final days of the independence referendum for the No campaign, will lead an end-of-day debate on Wednesday entitled "Scottish representation in the Union".

Last autumn, Mr Brown warned that a combination of devolving total control over income tax and banning Scottish MPs from voting on so-called England-only laws would be a "lethal cocktail" that was anti-Scottish and anti-British because it would lead to the break-up of the UK.

In next week's Adjournment Debate, the MP for Kirkcaldy and Cowdenbeath will speak on the delivery of the Vow on more powers, explaining how they could be delivered more quickly and effectively as well as the timetable for further devolution to Holyrood.

He will make proposals to improve the detailed legislation and call for important measures to be delivered before summer.

But the ex-PM, who will step down as an MP at the General Election, will also expose the "contradictions and confusions" that lie behind English votes for English laws(Evel) and call for the Conservatives and Liberals to resist banning Scottish MPs from Budget votes on taxation, which he believes will impose a second-class status on Scottish representation in the Union.

"While there are many important issues at stake in the pre-election debates - the future of the NHS, the economy and national security - it is vital the House of Commons debates what is happening to the United Kingdom as a whole and the attempt by the Coalition to restrict Scottish representation in Parliament."

In the next week or so, William Hague, the Commons Leader, is expected to unveil which of a number of options on Evel the Tories will choose.

It is believed that the Prime Minister is leaning towards the one that would introduce an English Grand Committee stage for legislation. While this would empower only English MPs to have the final vote on detailed changes to a Bill, it would enable all MPs to get involved in earlier stages and take part in the final vote on the overall legislation.

Scottish Labour MPs are scathing about Mr Cameron's approach on Evel; set out within an hour of the referendum result last September. They believe he is threatening the integrity of the Union simply to garner votes in English constituencies to stave off the threat from Nigel Farage's Ukip.

But the Tory leader insists that having been fair to Scotland in promising more powers, he now needs to be fair to England in restricting Scottish MPs on so-called England-only laws.

Recently, he made clear that he was determined to press ahead with Evel, particularly in light of the possibility of a post-election Lab-SNP alliance.

Describing Evel as "absolutely essential and doable", he said: "There have always been some people who've said this will break up the United Kingdom; it's nonsense. There's a way in which it can be done, which safeguards our constitution but delivers a situation where it is English MPs, who have the decisive say over issues that affect England. So it must be done."