Brits could wait 26 years until key post-Brexit trade deals all come into force, according to a new analysis of international negotiations.

An investigation into the average time taken for the United States, China, India, Australia and New Zealand to strike free trade deals shows the UK might be waiting until 2045 before all the agreements are in place.

The anti-Brexit Open Britain group, which crunched the numbers, argues that International Trade Secretary Liam Fox has already admitted his department does not have the capacity to carry out multi-negotiations, meaning deals with key markets would have to be struck one at a time.

According to the group’s analysis, that could mean it will be another quarter of a century until all the agreements are active.

Tory peer Lord Patten, former EU Commissioner, trade negotiator and supporter of Open Britain, said: “Trade negotiations are nasty, brutish and long. After a hard Brexit the UK will not be in a position to dictate terms to major economies like the US and China. 

“Under pressure from ministers to salvage something after Brexit, ministers risk being taken for a ride by President Trump and others who will insist we lower our food and environmental standards – and possibly open up our NHS – so that their industries can get a foothold in the UK.”

According to Open Britain’s calculations, the average length of trade negotiations are:

• India – 6 years and 11 months;

• China – 5 years and 9 months;

• Australia – 5 years and 1 month;

• New Zealand – 4 years and 7 months;

• United States – 3 years and 9 months.

The Government has repeatedly said its trade priorities are to negotiate a comprehensive agreement with Brussels, and then secure the rollover of the around 40 deals the UK benefits from by virtue of its EU membership.

But that has not stopped Fox from travelling the world to drum up in interest new markets ahead of the UK being able to being negotiations on new trade deals directly after Brexit. 

Last month, Australian Federal Minister for Trade Steve Ciobo said he wanted to begin talks on an agreement with the UK on March 30 2019 – the day after Brexit.

According to NewsCorp, Ciobo said: “The Australia-UK trading relationship took a big hit when the UK joined the European Community — especially our agricultural exports.

“So it will come as no surprise that Australia is determined to ensure that our limited access to the EU and UK markets is not further diminished as a result of the UK leaving the EU.”

The focus on securing a trade deal with the EU and carrying over existing agreements after Brexit has seen concerns raised over whether the UK will have the ability to begin negotiations with new trade partners in March 2019.

Fox raised the issue of his department’s resources in an interview in September last year, saying: “There are a number of countries who said they would like to move directly to a new free-trade agreement but we have said we are simply unable to do that at the moment.

“It requires the willingness of the country involved to want to move the process further on and it’s dependent on our own capacity in our own department.”

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SNP MP Angus Brendan MacNeil, chair of the International Trade Select Committee, warned that rushing to secure trade deals after Brexit could see the UK outmaneuvered around the negotiating table.

He said: “The time taken for various countries to negotiate trade deals is quite long really.

“Of course all countries are telling the UK at the moment that they’ll give them a quick trade deal but what they mean is they will give them a quick trade deal to the advantage of the experienced side and not to the inexperienced UK.”