It is easier than you might think to move a car factory abroad. Shipping containers and low loaders gobbled the Birmingham production lines of defunct MG Rover in the noughties. The machinery went to China. Staff retired or found other jobs.

In extremis, relocation is one option for UK car factories today. A no-deal Brexit, seen as the most likely outcome of trade talks this weekend, would be bad news for the industry. World Trade Organization tariffs on exports to the EU would be 10 per cent.

Which factories and communities are most exposed? The Big Six UK carmakers are reticent about publishing detailed figures for competitive and political reasons. But a broad-brush picture of vulnerability can be extrapolated from data provided by media, industry experts and the companies themselves.

Chart shows % of UK production sold showing UK carmakers: no-deal whiplash

Nissan, whose UK base is Sunderland, is in the toughest position. The Japanese group’s plant exports about 70 per cent of its cars to the EU — equivalent to 240,000 in 2019. Analysts said tariffs would make many of these vehicles uncompetitive on the continent. Toyota, based at Burnaston, Derbyshire, comes second, with likely EU exports of about 130,000 vehicles last year.

Two manufacturers of four famous British marques come next, gaining some protection from higher exports elsewhere. BMW, which makes Minis and owns Rolls-Royce Motor Cars, sells less than 50 per cent of UK output on the continent. The proportion is lower again for Jaguar Land Rover, whose Range Rovers win well-off customers in China and Russia. EU exports of 20 per cent were equivalent to under 80,000 vehicles in 2019.

JLR might look heavily staffed with 32,000 manufacturing-related workers, compared with about 7,000 at Nissan. But it has far more UK R&D specialists.

It is hard to predict the jobs impact of steep tariffs on EU exports at the Big Six. Their UK sales may rise after Brexit. But no-deal Brexit would plainly hurt the British plants of Nissan and Toyota. The whole industry could, meanwhile, be weakened by a collapse in EU exports, via the shared supply chain.

Industry pundits estimate employment by applying a multiplier of six to assembly factory workforces. That yields a figure of about 315,000 for the Big Six in the UK. A similar calculation suggests only 60,000 depend on fishing.