18/01/2014 03:47 GMT | Updated 19/03/2014 05:59 GMT

If We Leave the UK, We Risk Losing Our International Influence - For Good

I was a diplomat for 37 years. My experience over this time in many different countries is that if you want to further your country's interests in the world it pays to have contacts, knowledge and influence. The UK has all three in spades, built up over many generations and possibly more so than most other nations on earth. The idea of giving that up, to separate ourselves off from the ability to make a difference in the world and to support investment in Scotland makes no sense. As a proud Scot I can't understand the logic of reducing our country's influence in the world.

I was the UK Ambassador to Afghanistan, Saudi Arabia, Iraq and Sudan, and have served in Libya, Australia and the UAE. I know from experience that it was because I was acting on behalf of the UK that I could get access to the most senior government officials and the biggest businesses across the world.

As Commercial Attaché is Abu Dhabi I was, as a British diplomat, able to get access to senior officials in support of bids by Scottish companies such as Weir Pumps and many of the companies involved in the offshore oil industry.

In Saudi Arabia as British Ambassador I was active in promoting inward investment into Scotland and helping Scottish companies resist competition from US, German and French companies.

As UK Consul General in Riyadh I was involved in leveraging the influence of the UK to obtain the release of Scots citizens jailed in Saudi Arabia.

Smaller countries without the UK's clout and size cannot match what we currently have. This isn't an opinion, it's a fact. I know it be true from my time as a diplomat. Ministers and officials as well as big businesses in leading countries like the United States, China, Saudi Arabia, Brazil and India take the phone calls of UK ambassadors because as a country we have something they are likely to want. That isn't the case with smaller nations. This is the reality that Alex Salmond must wake up to.

Our UK ambassadors, who represent the whole of the UK, have access that other smaller countries do not. Our influence in so many organisations, such as NATO, the EU, the UN, the IMF and the World Bank, means other countries will open the door to us and let us make a case for investment in Scotland.

International diplomacy is all about getting things done. You scratch my back and I will scratch yours. It may not be pretty but it is the reality. The UK has the largest and most effective diplomatic network in the whole world, with an ability to get things done like no other. Why would we want to give that up?

If we leave the UK we lose that influence for good. The idea that the ambassador for a separate Scotland would have anything like the access or clout of a UK representative is simply not credible.

That influence isn't about prestige for the sake of it. It matters to jobs and investment in Scotland. Whether it's the UK Ambassador in the United States successfully lobbying in favour of the cashmere industry, or our representative in Tokyo fighting to protect Scotch Whisky, Scotland's interests are defended and promoted across the world by the UK.

The access and influence that we have as part of the UK creates jobs in Scotland and boosts our economy.

Being part of the UK has very real benefits to Scotland. We have a big voice in the world, but just as importantly we use that voice to promote Scotland around the globe and attract investment to our communities. People voting in the referendum should be in no doubt about what we would be giving up if we go it alone.

Scotland is well known and much admired across the world. We have our own distinct identity and we have the enormous benefit that comes from being part of the UK. Like so many other aspects of this debate, it is clear to me that we have the best of both worlds. Trading all that we have for a leap into the unknown seems to me a mistake we Scots would come to regret.