IT worked for Google and the medical profession, now ministers hope it can work for them too.

The SNP are to embed the mantra "Do No Harm" in their foreign policy if Scotland is independent, and will not allow Scottish defence companies to export arms to repressive regimes, Humza Yousaf, the SNP's External Affairs Minister, said last night.

The phrase is the guiding principle of the Hippocratic oath traditionally taken by doctors when promising to practise medicine ethically.

The concept, which dates from the fifth century BC, has been adopted more recently by Google, whose corporate motto is "Don't be evil".

The SNP plan to base their approach to world affairs on the Do No Harm philosophy, despite the concept of an ethical foreign policy proving notoriously difficult to put into practice.

When Labour won the 1997 General Election, foreign secretary Robin Cook declared: "Our foreign policy must have an ethical dimension."

It came back to haunt him after the Government decided to honour a contract to supply Hawk jets to Indonesia despite fears they would be used for repression in East Timor.

According to the Scottish Council for Development & Industry, Scotland plays a key role in the defence market, with 185 defence companies employing 12,600 skilled workers, and annual sales of £1.8 billion.

Speaking on the eve of a visit to Malawi and Zambia, Yousaf said an independent Scotland would pursue a partnership approach with other nations.

Writing in an online blog for the Sunday Herald, which is on our website today, he said: "We will be consistent in our compassionate approach to the world's poorest. Upon independence we will pursue a policy of Do No Harm - where our good work globally will not be undermined by the selling of arms to some of the world's most brutal dictators as has been done by previous UK governments."

The theme is being developed tomorrow by Angus Robertson, the SNP's Westminster leader.

In a lecture to the Institute for International and European Affairs in Dublin, he will say an independent Scotland would play a "positive proactive international role". He will say: "Sadly politics at a UK level is massively influenced by the anti-immigration, Europhobic agenda of Ukip and large swathes of the Tory Party, which is almost absent in Scotland. Their priorities are leaving the EU, walking away from European Human Rights commitments and ignoring the opening gulf in political priorities with Scotland."

The pro-Union Better Together campaign said it was ironic that the SNP is preaching 'Do No Harm' overseas while proposing to cause harm to Scots at home by leaving the UK.

A spokesman said: "We all know Alex Salmond loves nothing better than a good jaunt around the world at public expense. Do no harm abroad, but do as much harm at home seems to be his mantra."