Is David Cameron's announcement that an arrangement to enable 'English Votes for English Laws' (Evel) will be in place in time for the first budget of a future Conservative government is somewhat implausible.

Since the announcement that Scotland had voted 'No' in September's independence referendum, the Conservative leader has been guilty of simplistic and ill-considered rhetoric on this thorny constitutional issue and this is more of the same.

The issue is too complicated to be resolved in time for the first budget and it is disingenuous to suggest that it can.

The simple issue of what constitutes English laws is fraught with difficulty. The SNP argues, with some justification, that almost all budgetary decisions affecting England also affect Scotland via the Barnett consequentials.

Until a clear solution is found, it is not hard to see Westminster paralysed by disputes as Scottish MPs query votes said by the government to be English-only, or equally English backbenchers contesting why other votes have been designated as UK-wide.

Is the Conservative manifesto pledge a betrayal of the consensus achieved by the Smith Commission as both Scottish Labour leader Jim Murphy and the SNPs John Swinney have claimed?

That depends on whether you believe William Hague who says is being proposed is a further layer of check, with English or perhaps English and Welsh MPs having to approve any proposals affecting only English constituents before the whole parliament votes on them.

He argues that because no voting rights are being removed from Scottish MPs, this does not compromise Smith. However it would clearly create a two-tier system of MPs. Liberal Democrat leader Willie Rennie is surely right to warn that by diminishing the role of Scottish MPs and enhancing the voting rights of English and Welsh MPs, the Conservatives would risk destabilising Westminster and ultimately the whole UK.

These measures are presented by David Cameron as designed to avoid resentment and strengthen the UK family of nations. The basic constitutional unfairness caused by devolution is causing resentment, he argues, with greater powers for Scotland undermining the bonds and fellow-feeling that are the basis of the United Kingdom.

But rather than strengthening the UK, they are at least as likely to have the opposite effect.

Clumsy EVEL proposals could easily exacerbate suspicion of Westminster in Scotland. Rhetoric from the Conservatives south of the border about shutting out the SNP from government, should Scotland vote for considerable numbers of SNP MPs, is problematic enough. By instituting something approaching fiscal autonomy for England, this latest manifesto pledge could make the break up of the UK more likely. Many people might welcome this, but it is surely not Mr Cameron's intention.

The issue of what constitutes English laws and what EVEL actually means is a hugely complex question and undeniably needs to be addressed.

That is why it is sensible for the parties to address it in detail after the election by means of a cross-party, constitutional convention. But it is unhelpful, even reckless, to do so by means of soundbites and offering simplistic solutions to voters in the heat of a general election campaign.