Britain must rush to agree a trade deal similar to the one being hammered out between the EU and Japan or face having the UK’s £72bn-a-year car industry taken apart, a trade lawyer has warned.

The alarm has been sounded by ­Hosuk Lee-Makiyama, a former diplomat who has represented the EU at the World Trade Organisation and is ­co-author of the European Commission’s Trade Sustainability Impact Assessment on the EU-Japan trade deal.

He said Japan and the EU are close to sealing a deal – dubbed “cheese for cars” – which will give Japanese companies tariff-free access to European markets, an arrangement likely to benefit the country’s huge manufacturing base. In return, Europe’s farmers will get similar access to Japan.

The EU-Japan trade deal could be agreed in just six months and come into force before Britain bows out of the EU in 2019. Once in place it could suddenly make Japanese companies’ UK manufacturing plants less competitive than similar factories in Europe.

“In the case of a hard Brexit, there could be a tariff between the UK and the single market, whereas there will be none between Japan and the EU,” said Mr Lee-Makiyama.

“That has considerable consequences for the car plants at Sunderland and Swindon, because if you look at the supply chains of those plants they source a lot of parts from the single market, as well as Japan.”