It's in everyone's interests to have an honest discussion about the cost of doing business in Scotland, now and in the future.

Whether Scotland should be an independent country is not a question for Asda to answer; we are neither for, nor against, independence.

For us, the customer is always right. That's why it is right that our customers, colleagues and the people of Scotland decide their own future in a democratic referendum.

No matter the outcome of the referendum, people will still need groceries and, as a shopkeeper, I will do everything I can to continue to provide the best possible service at the lowest possible cost.

Our business employs more than 20,000 people in Scotland and 1.8 million customers shop with us every week. We spend more than £1 billion a year with Scottish suppliers. Like any business, we have regular conversations with Government about the costs of doing business and, like any prudent business, we plan ahead for many outcomes.

For Scotland, whether it's further devolution of power or full independence, it seems clear there will be change. My duty to the people we employ, serve and trade with is to adapt to that change as successfully as possible. Which brings me to the question I've been asked: what might the impact be on Asda?

We operate a single model across the UK. We think it is fair that the price you pay in Perth is the same as you pay in Portsmouth, irrespective of the cost of transporting goods.

By operating in a market serving 65 million customers we achieve major efficiencies and economies of scale and we use these to keep prices down. We operate in a single market. It is regulated and organised on a UK basis and our prices reflect our cost of operating in the UK.

Those who argue for independence understand that part of the deal is that Scotland would stand on its own, take its own decisions and balance its own books.

An independent Scotland would require us to establish a separate Scottish business, the principle that operates across the world. Walmart Mexico is a separate business from Walmart USA. Our business in Scotland would have to reflect our cost to operate here.

Already it costs more money to get groceries to people in Scotland, our taxes are higher and our margins are lower. Our systems are set up for one single UK market. These are not arguments for or against independence, but a simple recognition of the costs that change would bring.

I am not saying prices have to rise in an independent Scotland. I am saying that politicians of all sides need to work with business if they want to reduce the cost of doing business and in turn the cost of living. Recent experience is of changes being made that increase the cost of doing business.

Scotland's large retail levy is a good example: £95 million of additional tax which makes Scotland a more expensive place in which to do business.

To replace the amount taken off the bottom line by the levy, retailers would need to sell an additional £2 billion. That's not happening in this economic climate.

But the reality for Asda is that the impact of this cost is spread across our 18 million UK customers, rather than our 1.8 million Scottish shoppers.

I can't foresee a time that Asda wouldn't have a strong presence in Scotland and be fighting hard to keep prices low for Scottish consumers. So we will get on with doing what we do best, being shopkeepers.

Meanwhile, politicians could help by abolishing the large retail levy. It would recognise the need to make Scotland a more competitive environment and reward rather than penalise those retailers that invest capital in bricks and mortar and support supply chains in Scotland.

By working together we can get more young people into employment, support the Scottish food and drink industry, and ease the cost of living for people across Scotland.

No matter the outcome of the referendum, that's in everyone's interests.