Brexit Secretary David Davis has given the strongest sign yet that the UK is heading out of the single market and the EU customs union.

Mr Davis ignored jittery currency markets which have seen sterling slump as expectations of a hard Brexit have grown, and stated the UK could hope to be “incredibly successful” outside of the single market.

Speaking in the Commons he also signalled that the UK would want to strike trade deals immediately, indicating Britain would leave the EU customs union.

Mr Davis was giving a statement following announcements at Tory conference that Britain will trigger Article 50, launching official Brexit talks, before next March.

He batted away calls from Tory, Labour and Liberal Democrat MPs for Parliament to have a say in triggering the article and on the terms of Brexit negotiations.

But pushed on his preference for staying in the single market, something many see as vital for the UK’s economy, Mr Davis did say: “It is not necessary to be a member of the single market, to trade incredibly successfully in the single market.”

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Asked again about the issue, he said: “All forms of free trade are beneficial - whether it is based on mutual recognition, single legal areas or any other mechanism of free trade.”

Mr Davis later went on to say that the UK would seek free trade deals quickly after Brexit, something that would be impossible if the country wants to remain inside the customs union, which allows goods passing EU borders to avoid levies.

After Theresa May’s conference speech, in which she signalled immigration was a primary concern over retaining access to the single market, pound sterling fell to its lowest level against the dollar since the beginning of July.