If 23,000 Scottish businesses are cheating on their tax, as is claimed by Her Majesty's Revenue and Customs (HMRC), that should concern us all.

The figures apply to small and medium enterprises (SMEs) and the tax man is urging the 7% it believes are breaking the law to get their house in order. "Help is on offer to people who are confused," HMRC says, with only a hint of implied threat.

While the announcement is being styled as a crackdown, the hope is that companies will come forward to put their own affairs in order.

Loading article content

The initiative is to be welcomed. Tax evasion is not a harmless defiance of the authorities as classically depicted by the likes of TV's Del Boy.

Instead, companies which deliberately evade their legal duty to pay tax defraud us all, defaulting on their responsibility to help fund services such as schools, roads and the NHS.

Not only are they cheating the public, they are also cheating their competitors, gaining an unfair advantage over the majority of responsible businesses which accept their social duty and follow the rules.

Business leaders warn that the system is too complicated and point to the fact that another 15% are paying too little because they don't understand what they owe. There may be a case for taxes to be made clearer.

But there is no excuse for those Scottish companies who the taxman says are resisting paying taxes they are legally due. This is not the unethical but legal area of tax avoidance, of the type which has seen, for example Amazon paying relatively tiny tax contributions despite sales of £4bn. It belongs to us all and it should be paid. Tax evasion should be as unacceptable as smoking in public buildings or defrauding the benefit system.

It is right that HMRC should pursue those who break the law. But the demand should apply to businesses of all size.

HMRC faces a problem of public perception due to the huge damage done by deals which have seen large companies writing off their tax dues by agreement with the authorities.

We learned in 2010 that Vodafone persuaded HMRC to write off £6bn of a £7bn tax liability, which offends against any sense of fairness. Four other large companies also struck deals to avoid tax which they were legally due to pay.

The National Audit Office has investigated the deals and believes they were "reasonable", but the public is not allowed to know the companies involved or the sums they were excused from paying.

Under pressure from the Lib Dems, George Osborne promised last autumn to spend £154m funding an "army of investigators" to tackle corporation tax avoidance. But this is utterly misleading, given that funding was cut in 2010 by £2bn, including 10,000 job cuts. These were followed by a further 5% cut in this June's spending review.

If it is to make an impact on SMEs which cheat on tax, it is vital HMRC has the resources to do so properly, and to challenge not only small businesses, but the very large companies where they face opponents with more expertise and resources. While these firms are perceived to get an easy ride, the perception remains that some tax targets are more equal than others.