A polling expert in Kent who has informed government policy on British and US elections has said America could be on the brink of a constitutional crisis in the event of a close result in the country’s presidential race.

Sir Robert Worcester, a former Chancellor of the University of Kent who lives in Allington Castle, near Maidstone, said he believes Hillary Clinton will beat Donald Trump in the contest for the White House but warned there could be lengthy legal challenges.

As US voters go to the polls today, he said he has never seen a presidential race like this and that currency and share values could plummet in the event of a Trump victory.

Sir Robert, a native of Kansas City who founded polling firm MORI when he came to Britain in 1969, said Mr Trump had emerged as “the best of a bad bunch” of Republican candidates who were largely unknown to most voters.

He said the election of the next president could be delayed if Mr Trump wins more of the people’s votes but Mrs Clinton takes victory by virtue of gaining more electoral college votes, the means of deciding the president.

He said: “I think it is going to be a very interesting result.

“One concern we have is that we could have a repeat of the Gore v Bush election, where Gore took the popular vote but Bush took the electoral college.

“Back then, Gore said he would play by the rules and stepped aside in a gentlemanly fashion and Bush became president.

“I don’t think it is in Donald Trump’s character to go that way if we have a similar situation, where he gets the popular vote but Clinton takes the electoral colleges.

“Then we are looking at a serious constitutional crisis and everything will be up in the air for months.”

Sir Robert, who is a Deputy Lieutenant of Kent, said businesses in the county may be in for a sharp shock as the election result becomes known.

He said: “If Trump wins there is going to be an impact on currency and shares. There is no question about that.

“The world will be like it was post-Brexit, holding its breath to see what will happen. It will devalue the dollar and may strengthen the pound but I don’t think that will last long.”

Sir Robert believes one of the biggest reasons for the rise of Donald Trump has been his support of gun-ownership in the US, which many voters think Mrs Clinton is against.

He said: “From the beginning he was saying he is a great believer in the Second Amendment. He is constitutional when he wants to be.”

Yet despite concerns about international diplomacy, Sir Robert thinks the special relationship between the US and UK will be unaffected whoever becomes president.

He said: “However, at the highest level, it will be difficult for Theresa May to get a word in with Donald Trump shouting at her. He’s a known misogynist.

"At that level, it will be awkward, although he claims to be women’s best friend.”