Abbott was promoting an article he wrote for the British Spectator magazine last October – the magazine’s fourth most-read article of the year. The article was reprinted in a free magazine distributed across Britain this week by Wetherspoon, a big British pub chain. The owner of Wetherspoon is a Brexit backer, who last year announced he would replace all French champagne sold in his pubs with UK and Australian sparkling wine. Abbott's column argued the UK should be more willing to embrace a "no-deal" scenario as it would "let Britain set its own rules" on trade (he also argued for continued free movement of European workers into Britain). The tweet caught the attention of some Conservative MPs, including backbencher Michael Fabricant who retweeted it with approval.

However Prof Portes replied: "Australia's trade with the EU is worth about 7.5% of Australian GDP. UK's trade with the rest of EU is worth more than 30% of UK GDP. Anyone with a basic grasp of economics (not @TonyAbbottMHR it seems) should spot the problem." Former PM Tony Abbott's writing in UK pub magazine Wetherspoon. The tweet also sparked a reply from Dmitry Grozoubinski, who was a negotiator for the Australian government at the World Trade Organisation in Geneva during the Abbott and Turnbull governments, and is now an independent consultant on international trade. Grozoubinski replied to Abbott: "Australia's exports to the EU are dominated by raw commodities and agricultural products for which it enjoys country specific quotas the UK won't get. "There are few JIT [just-in-time] EU-Aus supply chains and no Ro-Ro [roll-on roll-off haulage truck] ferries between Perth and Rotterdam.

"You are embarrassing. Stop." Grozoubinski pointed out that Australia has a specific deal allowing tariff-free lamb meat sales into the EU, another bilateral trade deal on wine that allows Australia to export wine in bulk and bottle in the EU, thus minimising tariffs, and is also negotiating a free trade deal with the EU. He told the Sydney Morning Herald and The Age that the biggest difference was "proximity and the nature of trade". "Australia and the EU sell goods and services to one another," he said. "The UK and EU make things together. If you slapped a hard border between Victoria and New South Wales overnight, it would be really disruptive."

Illustration: Matt Golding Credit: Abbott is on the advisory board of a pro-Brexit think tank in the UK, the Initiative for Free Trade, whose stated mission is "to recapture the moral case for open commerce" and make Brexit "a catalyst for a freer global trading order". Grozoubinski has used sheep meat as an example of a British industry that would be dealt a severe blow by a no-deal Brexit. The UK's sheep sector employs 34,000 people on farms and more than 11,405 in allied industries, and more than 90 per cent of its sheep meat exports go to the European Union. But if the UK leaves the EU without a withdrawal deal its exporters will have to pay EU import tariffs that would increase the price by about 45 per cent per kilo, making it entirely uncompetitive with New Zealand and Australian meat on the continent.

No deal would be "a disaster" for the UK's sheep sector, as it would be slapped with EU import tariffs. Credit:Jason South "If you were a business and overnight you lost access to 99.7 per cent of your foreign customers, that would be a disaster," said Grozoubinski. "That’s what’s coming down the pipe." Loading Professor Alex de Ruyter, from Birmingham City University's Centre for Brexit Studies, said the UK could be forced to drop import tariffs on food to prevent shortages and to cope with the abrupt change to its customs system. About half the country's food is supplied by the EU, and new excises once the UK left the EU's customs union would require extensive new checks at the borders, but the UK's customs system would struggle to handle the extra work.