He is expected to argue that Britain would be in a powerful position to influence international policy after Brexit and usher in more liberal rules of commerce because the UK is the fifth biggest economy in the world.

In remarks to investors last week, Dr Fox said: “One hundred and fifty years ago the UK was the world’s biggest trading nation, and now we will lead the charge again for freer and fairer global trade.”

The Cabinet minister’s intervention represents a significant moment in Theresa May’s effort to carve out a prosperous future for Britain outside the EU.

Mrs May and other ministers are focused on ensuring the UK gets a good trade deal with Brussels and leaves the EU on the best terms.

Many leading banks and businesses want the UK to keep its membership of the single market, or to retain as close ties as possible, in order to make it easier for them to continue trading across the EU.

There are signs, however, that senior ministers are ready to accept that retaining full access to the single market will not be possible.