The hippest, most progressive restaurants, pubs, coffee shops and delis have been doing it for years.

Now, for the first time, transport companies operating into and out of Scotland are set to serve customers food sourced and prepared in Scotland.

First off the starting block are Scotland's two new rail franchises - ScotRail and Caledonian Sleeper - who from April 2015 will be using locally sourced produce for on-board catering and at some stations to promote the best of Scottish food and drink to travellers. Menus will feature a range of items, from shortbread and biscuits and ice-cream to fish and vegetable and meat dishes supplied by smaller artisan producers who are normally neglected by unwieldy central sourcing policies.

The welcome move follows a letter sent by Richard Lochhead, cabinet secretary for food, to Scotland's rail franchise holders and airport, port, ferry, bus and train station operators urging them to do more to promote good quality Scottish produce in the run-up to the Year of Food and Drink 2015, which starts on January 1.

The new ScotRail franchise will focus on the best brands and primary produce from the best producers in the country. Additionally, the introduction of ToGo kiosks at larger stations will sell bakery goods and snacks made in Scotland alongside hot and cold drinks. ScotRail has also committed to promoting Scotland's food and drink industry by producing guides.

The Caledonian Sleeper franchise has engaged The Food and Drink Hub, the Cumbernauld-based food and drink distributor for Scottish micro, small and medium companies. This means customers can experience a wide range of Scottish products from those small producers who are not as visible in supermarkets and larger shops due to economies of scale.

Mr Lochhead said: "I want other operators to follow the good example being set by ScotRail and Caledonian Sleeper.

"I challenge them all to consider adopting a pledge to show visitors and the wider public their commitment to playing a part in Scotland's journey towards becoming a Good Food Nation."

Peter Strachan, Serco's Managing Director of the new Caledonian Sleeper service, said:

"We're really excited about the hospitality service that we are going to create for passengers on the Caledonian Sleeper. The service will be emblematic of all that's best about Scotland and a key part of our plan is to promote and support small and medium-sized Scottish businesses by sourcing local products and produce from them."

Tesco, meanwhile, is promoting Scotland's Year of Food and Drink 2015 with a special logo on iconic Scottish products in the run up to Hogmanay in 200 Scottish stores. The supermarket chain has its own dedicated local sourcing office based in Livingston, West Lothian.