UNITED STATES President Donald Trump pledged $5,000 (£3,700) to every adult US citizen if his Republican Party wins both chambers of Congress in November’s mid-term elections.

The possibly illegal offer was made during a speech by President Trump on Wednesday evening at the Republican Party’s first ever convention in the middle of a US presidential term. 

President Trump gave no details during his speech in Dallas, Texas on how the plan would work or where the money would come from.

He said: “If the Republicans win the House of Representatives and the US Senate, both of them, I will issue a dividend to every adult citizen in the US for $5,000 (£3,689).

He said: “We don’t want you going to Canada to spend the money.

“We don’t want you going to China, to Germany. You got to spend the money in the US.” 

It is not clear how the spending would be monitored.

Democrats and other critics questioned the legality of the plan and labelled it an “empty promise.” 

There are nearly 270 million US adults, which means a $5,000 payout would cost the US government around $1.3 trillion (£960 billion).

Questions over whether his plan was possible have started to be asked — especially as prices rise in the US, a direct result of the illegal and unprovoked war that the US and Israel launched against Iran in February.

Iran’s retaliation has included attacks against US bases and allies in the Gulf — but crucially, it has largely closed the Strait of Hormuz where about a fifth of the world’s oil and liquefied natural gas used to transit.

It is not the first time that President Trump promised such payouts — he has previously proposed $2,000 (£1,400) cheques to be funded by tariff revenues. These payments have never materialised.

US federal laws prohibit payments that are intended to influence voting.