One of Donald Trump’s most senior advisers has told Britain it must scrap EU food standards on genetically modified crops and chlorine-washed chicken if it wants a successful post-Brexit deal with the US.

Speaking at a conference hosted by the Confederation of British Industry on Monday, US Commerce Secretary Wilbur Ross said that other areas that could pose problems to negotiations between the US and the UK after Brexit, included "passporting" of financial services, and future trade tariffs.

But he did say that he hoped the US could become the UK’s number one trading partner after the split, especially considering existing substantial trade flows between the two countries.

He said that it was critical that US interests must be taken into account when finalising an exit deal with the EU, whatever such an agreement might look like.

“It is ... important that an eventual Brexit agreement takes into account our commercial interests, and does not hinder development of a closer post-Brexit US-UK relationship by continuing divergent standards and regulations and other protectionist measures,” he said.

But Mr Ross also said that it would not be possible to identify exact points of contention until it is clear what form a deal would take. He said that he hopes that a free trade agreement between the US and the UK would take fewer than 10 years to negotiate.

Mr Ross' speech concluded a five-day visit to the UK, during which the commerce secretary met with Prime Minister Theresa May as well as senior ministers including Philip Hammond, Boris Johnson, David Davis and Liam Fox.

His comments come a day after a massive document leak which showed that Mr Ross had been doing business with Vladimir Putin’s son-in-law through a shipping venture in Russia.