David Cameron will today warn English voters the SNP 's new powers could impact their lives . David Cameron will today risk infuriating the SNP by vowing to conduct an annual review of the fairness of the Scottish government ’ s policies on the rest of the UK . A Conservative government would create a new principle to ensure decisions by Holyrood do not have an ‘ unforeseen detrimental effect ’ for people south of the border , he will say . The Prime Minister will tell voters in England that new powers for the Scottish Parliament mean it ‘ can now have a big impact on your job , your income , and investment in your area ’ . Mr Cameron will call the idea the ‘ Carlisle Principle ’ – named to reflect the sort of border communities in the rest of the UK that could be particularly badly affected by decisions taken by the Scottish government . There has been growing resentment in England and Wales at the ‘ apartheid ’ between those living north and south of the border in areas such as healthcare and university fees . For instance , cancer drugs have been made available on the NHS in Scotland that are not prescribed elsewhere , meaning taxpayers in England and Wales are contributing to funding them , but not benefiting . The Scottish Parliament ’ s new powers to cut air passenger duty could lead to air travellers and airports in the north of England being unfairly disadvantaged – and require targeted tax cuts , Mr Cameron will say . However , Scottish Nationalists are likely to accuse Mr Cameron of wanting Westminster to ‘ mark the Scottish Parliament ’ s homework ’ every year . He will also be accused of seeking to stoke anti-Scottish sentiment in the rest of the UK – and throwing fuel on the fire of Scottish nationalism . The Tory manifesto promises to introduce a principle of ‘ English votes for English laws ’ , meaning English MPs will be given a veto over legislation relating solely to England . Under Mr Cameron ’ s latest plan , a formal assessment would be made by the Treasury and Cabinet Office each year of the impact of Scottish policies , including tax rates , business levies , university tuition fees and healthcare . Mr Cameron risks the wrath of Scottish National Party leader Nicola Sturgeon ( pictured above ) with his announcement . The Chancellor will tell MPs ‘ what action is needed to make sure there is no detriment to the rest of the country ’ . The Prime Minister , on a campaign visit to the North West , will insist the plan will not stop the Scottish government taking the decisions it wants . ‘ In the Scottish referendum , we made a clear promise to devolve more powers to the Scottish Parliament , ’ Mr Cameron will say . ‘ After we won that referendum , we kept our promise , and agreement was reached – for the first time – between all five of Scotland ’ s major parties to give the Scottish Parliament extensive new powers . ‘ But as we go further in devolving powers to Scotland , we need to make sure devolution works for all the other all parts of this country too . ‘ Today I want to set out a new principle – you could call it the Carlisle Principle – that we will make sure that there are no unforeseen detrimental consequences to the rest of the country from Scottish devolution. ’ Boris Johnson and Sir John Major will enter the election fray this week as the Tories try to bolster their campaign . Sir John will warn of the dangers of a Labour-SNP government . The ex-premier could be deployed to speak as early as tomorrow . Later in the week , David Cameron is due to make a first high-profile campaign appearance with Mr Johnson . There are growing calls from Tory MPs for the London mayor to be ‘ weaponised ’ . David Cameron has revealed he is locked in a high stakes battle : over ear-piercing . While contesting a general election campaign , he is also in a 'fight ' with eldest daughter Nancy about when she can have her ears pierced . The Prime Minister also admitted he does not want his children to follow wife Samantha in having tattoo . In an interview with the Sun , Mr Cameron said his children 'take the mickey out of me daily ' , including mocking his TV and music choices . 'To them I 'm just a normal dad , who they think is a bit square and sometimes embarrassing . It 's very sobering to come home to after a day in the office , ' he said . 'They rib me about , you know , anything from my CD collection to what I watch on TV . ' Nancy is due to start secondary school in September , and wants to have her ears pierced . Mr Cameron said : ' I 'm in that fight with Nancy at the moment . We 'll probably reach an agreement over what age she can have them done . We 're in negotiations . ' His wife Samantha has a small tattoo of a dolphin on her right ankle , which she had done while travelling as a student . She has said it would 'fine ' if her children copied her . But Mr Cameron said : ' I 'm not a big fan . I love Samantha 's tattoo , it 's very small , very discreet . But I 'd be a square dad and tell the children to think very carefully about it . '
A Tory government would create a new principle to review SNP policies . Prime Minister to tell English voters SNP 's powers could impact their lives . There has been growing resentment at 'apartheid ' between north and south . Cancer drugs are available on NHS in England but not Scotland and Wales .