Chris Grayling is the Secretary of State for Transport (Image: GETTY)
Mr Grayling said the country of around three million people would be able to "dictate" the UK's terms of trade with the commonwealth. He warned of the stark risks of the UK being locked into a customs union with the EU, such as handing over control of trading policy to the 27 EU member states. MPs could vote on staying within a customs union in series of indicative votes today in Parliament.
Mr Grayling said: "Are we really going to accept the situation where the government of Lithuania has more power over our trading relationship with the Commonwealth than our government does?
“That is the reality of the customs union."
In an interview with the Telegraph he added: "People who sign up to the customs union are basically signing up to single market as well.
“And that leaves us mostly in the European Union, it certainly does not give us control of our own laws."
Chris Grayling has warned against joining a