Tackling corporate tax avoidance is set to become a primary issue for the new Westminster government, as it emerges that three million shoppers are now boycotting firms who do not pay their 'fair share'.

Tackling corporate tax avoidance is set to become a primary issue for the new Westminster government, as it emerges that three million shoppers are now boycotting firms who do not pay their ‘fair share’.

Data seen exclusively by The Herald suggests that half of all Scots have actively shunned big global brands in the last year, with a significant proportion objecting to controversial tax arrangements at companies such as Amazon, Starbucks, Google and Vodafone.

Ethical Consumer, which carried out the research with YouGov, said tax avoidance was the third most popular reason for all personal boycotts in early 2015, with a third of students and 22 per cent of 18-34 year olds UK-wide taking a stand. The organisation also found that a quarter of Scottish shoppers choose to support local shops and suppliers every week while 21 per cent are attracted to retailers for their "responsible" reputation.

It confirms a growing public hostility towards tax avoidance, putting it on the agenda for a potentially fragile new government to trying to build trust.

The annual 'Great British Money Survey' reported this week that 65per cent of respondents believed a company engaged in tax avoidance was unethical. Bruce Davis, co-founder of ethical investment platform Abundance (www.AbundanceInvestment.com) which sponsored the research, said: "When looking at the activities of a business they might invest in, more people in the UK see tax avoidance as unethical than pornography or arms dealing."

Meanwhile most voters in marginal constituencies, 84 per cent, believed it "all too easy" for big corporations to dodge tax, according to a poll commissioned by the charity ActionAid.

The survey found that 64 per cent of all respondents thought it was "very important" for the new government to raise fines for companies escaping tax in the UK.

Heather Webb, researcher at Ethical Consumer, said: "Tax avoidance boycotts are on the rise because the scale and the amount of money leaving the UK are extremely high. People are driven to boycotting companies when they feel there are very few options left in getting their message through."

Ms Webb said the creation of the Fair Tax Mark, awarded by an independent organisation to companies with ethical tax policies, was a sign that boycotts worked. But she added: "The issue isn't going away."

Nick Bryer, Oxfam's head of UK campaigns and policy, said tougher action "should be a no-brainer" for politicians, while Christine Allen, head of policy and advocacy at Christian Aid, said: "Politicians of all parties should heed the extraordinary level of public demand for action against this scandal of our time."

The Coalition Government introduced a 25 per cent "Google tax"on large company profits moved abroad, but all the mainstream parties pledged to go further during the election campaign.

The Liberal Democrats were the most vocal, saying they would invest more in HM Revenue & Customs and push for "greater tax transparency" from multinational companies.

The Institute for Fiscal Studies, however, said promised measures on tax avoidance were "vague" and "unspecified" across the board. Voters were also unconvinced: almost two thirds of respondents in the ActionAid poll said none of the parties had done enough to confront the problem.

Nicola Sturgeon will use her party's spike in Westminster seats to ask for more tax powers to be devolved to Scotland, while her party's manifesto included support for a crackdown on tax avoidance.

But critics rounded on the Scottish Government in 2013 after it paid Amazon £2.5m in grants to set up its giant facility in Dunfermline. This was more than the £2.44m corporation tax paid by the online retailer on sales of £4.2bn the previous year - a rate of just 0.1 per cent.

So what are the alternatives? For those wishing to boycott Amazon and its subsidiaries Lovefilm and Audible, Ethical Consumer (EC) has given plaudits to Blackwells and The Book People in the book sector, while John Lewis and Mattel score well for toys. Games Planet was given the best rating among retailers of PC and video games, and Netflix was among the high scorers in film/TV streaming.

Starbucks, which has 59 cafes in Scotland, has also come under fire for reporting minimal profits since it came to the UK in 1998, despite sales of £3bn, to keep tax bills low. EC recommends independent coffee shops and the AMT chain as more ethical alternatives.

Meanwhile, the first 'fair' smartphone has launched in the UK to challenge the likes of Vodafone and Apple, who have also faced scrutiny over their tax affairs. The Cooperative smartphone is built using minerals from conflict-free zones in factories with good working conditions, though its software is powered by Google, itself a target of anti-tax avoidance boycotts. With no upfront cost for the handset, contracts start from £20 a month for 200 minutes, unlimited texts and 500mb.

Another option is the People's Operator, which claims to offer (until 1 June) the UK's best 30- day Sim-only deal at £3.99 per month. The brainchild of Wikipedia founder Jimmy Wales, TPO allows you to choose a charity to receive 10 per cent of your mobile spend each month. However, the deal reverts to a standard price of £14.99 after the first two months.

Ethical spending rose 9 per cent in 2013 to put the value of the market at £32.2bn, the latest Ethical Consumer report found.

It added that the ethical financial sector grew by 6 per cent and is now thought to be worth at least £43.2bn.

Much of that has been fuelled by the rising popularity of credit unions, which rose in value from £807m to £2.04bn between 2012 and 2013.

The value of ethical banking however actually fell by around £22m during a period of considerable turmoil for the Cooperative Bank, the UK's biggest ethical finance player.