There's an ideological battle brewing between local food producers and their supporters and a certain London-based restaurant critic who, in an extract from his upcoming book published in a Sunday newspaper, claims that modern concerns over food miles are misdirected, that eating imported produce can be more sustainable than going local, and that we have to face up to the fact that other countries simply have better climates than ours for growing certain foods.

Such as lamb and dairy – both of which happen to be part of Scotland's agricultural DNA.

Jay Rayner floats the idea that – whisper it – localism is dead, arguing that it won't save the planet or help feed the seven billion people on earth. Since we're already consuming our culture from all parts of the world, he says, we may as well get used to the idea of doing the same with food.

Our man in London writes that New Zealand has a better landscape and climate for rearing lamb and apples than Britain; a strawberry ripened beneath the winter sun of Morocco can have a smaller carbon footprint than one raised in a British polytunnel; even potatoes can never be completely locally grown if you live in a large city, and the foodprint's roughly the same whether you get them from, say, Cambridgeshire or Cairo.

Rayner goes on to suggest that basing our food purchases on seasonality and a desire to support the local economy is merely aesthetic, and doesn't support the food miles argument so championed by what the writer describes as "goggle-eyed food warriors" who have "built entire patterns of behaviour around the idea of seasonality".

Needless to say, such rhetoric is a red rag to the bullish Mike Small, founder of the Fife Diet local eating experiment and author of Scotland's Local Food Revolution – also to be published next month. The usually mild-mannered activist for the relocalisation of food production can hardly contain his outrage at the suggestion that community food initiatives are a waste of time and resources. "It's absolute gibberish," he tells me. "If we continue to rely on faceless people in faraway places to feed us, we cannot hope to trace the provenance of what's on our plates, or be assured of its wholesomeness."

Rayner cites as evidence a report (which Small says has long been discredited) on the energy and emissions performance of New Zealand's agriculture industry, which concluded that lamb, apples and dairy produced in New Zealand and shipped to Britain have a smaller carbon footprint than the equivalent products produced in Britain.

Using a wide sample of apple farms both in the UK and New Zealand, the researchers of the report found that the weight of nitrogen fertiliser used was roughly similar in both countries (80kg per hectare in New Zealand to 78kg in the UK) but that in New Zealand they were getting a yield of 50 tonnes per hectare, against 14 tonnes in Britain. Where lamb was concerned, yield was higher in the UK than New Zealand, but so was nitrogen fertiliser use by a factor of more than 13. From this Rayner inferred his localism-is-dead theory, conceding that it will be a difficult truth for some to swallow.

But Small says if we take into account land appropriated abroad to satisfy our demand for out-of-season fruit and vegetables – strawberries from Morocco or green beans grown in Kenya, for example – then food contributes even more to the UK's "foodprint". Flying accounts for only 1% of UK food miles, but generates 10% of food transport C02 emissions. Shipping is also a major problem, he says. The amount of sulphur oxide pollution that comes from the 15 largest ships equals the combined amount from all the cars in the world.

"When we talk about food miles we are not just talking about air freight; we are talking about the whole journey between gate and plate, including the endless shuttling between home and the supermarkets," he says.

The issue of food miles tends to focus only on emissions, but it's also an issue of transparency, accountability and democracy. I agree with Small when he says where our food comes from has become a massive political and consumer issue in Scotland and that intelligent, knowledgeable food people are appearing everywhere.

Many of us are rightly proud of the progress we've made in reconnecting ourselves with food and food provenance, and in embracing the concept of food security. There has been a real focus on food in Scotland since the government's first national food and drink policy was launched in 2009, and a raft of local growing and sharing initiatives such as Nourish, SAGE, Locavore, FareShare, Blasda and so on. These are surely the signs of a nation that is growing in confidence at grassroots level.

I like to think our London columnist has done us a favour. When you're threatened with something precious being snatched away from you, you hug it all the closer.

cate.devine@theherald.co.uk

Twitter: @catedvinewriter