THE House of Lords is warning that the controversial English Votes for English Laws system risks damaging the Union while Nationalists claim it could be used to deprive Scots MPs a say over Brexit.

A report for the Lords Constitution Committee said a planned autumn review of the process - which strips Scottish MPs of the right to vote at certain stages of bills dubbed 'England only' - should be delayed until 2020 when the impact of the changes could be fully determined.

Committee chairman, former Tory Scottish Secretary Lord Lang of Monkton, said it was not "ideal" that English Votes for English Laws (EVEL) had failed to secure cross-party consensus when it was introduced last year.

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His committee's report concluded that if it were to "strengthen rather than weaken the Union" it was essential EVEL attracted support from all parties while ensuring "the procedures have no demonstrably negative effects on Parliament’s role as the centre of the political union, representing the interests of all parts of the United Kingdom”.

“Attempting to provide a separate voice for England through the membership and institutions of the UK Parliament carries risks," it warns.

Commons votes relating to Brexit could prove to be a "stress test" for the procedures, the peers said, and if the mechanism is retained the "technical and constitutional" aspects should be examined by a joint committee of MPs and peers after the 2020 election.

The EVEL process is aimed at ensuring that laws can only be passed if they are backed by a majority of MPs from the nations directly affected by the legislation as some measures passed in Westminster do not affect all parts of the UK as a result of the devolution process.

The policy led to claims that Scottish MPs are now “second class”.

Kirsty Blackman MP, SNP spokeswoman on the House of Lords, said the reform created "created two tiers of parliamentarians and has led to SNP MPs being locked out of important debates".

She added: "The idea that Brexit-related issues will provide an ideal "stress-test" for EVEL is truly baffling and the notion that Scottish MPs representing an area of the UK that voted overwhelmingly to remain in the EU could be denied a vote on important aspects of legislation that impacts the whole of the UK, such as the Great Repeal Bill, is absurd.

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"The UK Government must urgently establish a set of comprehensive proposals that all parties can support and should be clear that Scottish MPs will be given a voice in all aspects of the UK's negotiations on the EU so that we can protect our constituents and Scotland's relationship with Europe."

A spokesman for the UK Government said it was committed to a stronger Union and a "fair settlement for the whole of the United Kingdom".

Peers found no evidence that Evel had altered perceptions of a democratic deficit in England.

They said: “It remains our view that it is too soon to know whether EVEL and the ‘devolution deals’, separately or in combination, will provide an answer to the English Question.”

David Cameron faced accusations of betrayal after he announced plans to introduce EVEL less than an hour after Scotland voted to remain within the United Kingdom in 2014.

Critics pointed out that the policy had not been included within the "Vow" offering more powers to Scotland and signed by the Prime Minister before polling day.

But the Conservative Government forged ahead arguing that the previous system had been unfair because it permitted Scottish MPs vote on issues that did not directly affect their constituents.

Ian Murray, Scotland's only Labour MP, said the committee report showed how "short-sighted" the Tory government had been.

Read more: Hard Brexit 'could cost Scotland £5bn in exports'

He said: "EVEL was a knee-jerk reaction by David Cameron to UKIP's English nationalism and has created two classes of MP for the first time, stoking the kind of resentment that Scottish nationalists thrive on. Even though they were previously great supporters of EVEL.

"However, rather than kick a decision into the long grass, EVEL should be scrapped now.

"It's unnecessary, unworkable and undemocratic and we don't need another four years to tell us that."

The report did find that EVEL did not create any constitutional barriers to a Scot becoming Prime Minister in the future.

Peers are calling for a joint committee of MPs and members of the House of Lords be created to undertake a thorough review of EVEL,“including an assessment of its impact on perceptions of fairness in England, and in the other nations of the UK."

Opponents of the policy have long argued that few, if any, Bills are genuinely "England only" with no repercussions for other parts of the UK.

It created new stages in the legislative process.

All MPs can still speak and vote at the previous stages but only English MPs are allowed to vote in the new phases where the Speaker declares a bill, or part of a bill, is English only.

England's size creates huge knock-on effects in Scotland, Wales and Northern Ireland, they warn.

Supporters of Evel, however, point to the controversial 2004 vote to increase tuition fees in England, passed with the backing of Scottish MPs.

Evel was designed to answer the ‘West Lothian Question", famously posed by the then Labour MP for the area Tam Dalyell, who asked why devolution would leave him able to vote on issues like health in the Lancashire town of Blackburn, but not the West Lothian one of the same name.

A UK Government spokesman said:

"The Government is committed to a stronger Union and a fair settlement for the whole of the United Kingdom, and has delivered on the manifesto commitment to introduce English Votes for English Laws. The Leader is grateful for the Committee's report, and is taking their comments into account as part of the technical review into the procedures that introduced English Votes for English Laws."