Donald Trump's son says his father's run for the White House is a 'step down' in his career

Speaking after the third presidential debate, the nominee’s son slipped up again

Donald Trump Jr, 38, has increasingly stepped into the spotlight on his father's behalf (Reuters)

Donald Trump’s eldest son said that his father’s run for the presidency was a “step down” from his business career.

Speaking to Fox News after the third presidential debate on Wednesday night, Donald Trump Jr, he emphasised that his father was effectively giving up a successful job already.

“Unlike Hillary Clinton, who's gotten very rich being a politician, peddling American influence, he hasn't — this is only a step down,” Mr Trump said in Las Vegas.

He added that his father has spent his whole career “creating jobs” and helping American workers, and that if he had spent his whole life as a career politician, he would be “the greatest politician in the history of the world”.

The Trump campaign member was praised for a rousing and passionate speech about his father at the Republican National Convention in July, but has caused controversy in more recent weeks.

The businessman’s son and Trump Organisation executive was strongly criticised for sharing images on social media which compared Syrian refugees to Skittles sweets.

“If I had a bowl of skittles and I told you just three would kill you,” he tweeted. “Would you take a handful? That's our Syrian refugee problem.”

He also shared the image of Pepe the green Frog with Mr Trump’s face, a meme which has recently become associated with the white supremacist movement.

During an interview with the Pittsburgh Tribune Review about why his father has not released his tax returns, Mr Trump did not toe the party line - that the tax returns would be released once they had been audited.

He replied: “Because he's got a 12,000-page tax return that would create... financial auditors out of every person in the country asking questions that would distract from (his father's) main message.”

After the second debate, younger brother Eric Trump insisted to CNN that his father had paid millions of dollars in tax, and that he had personally seen his father’s tax returns.

Mr Trump Jr was sat in the front row of the third presidential debate at the University of Nevada, alongside his sisters, brothers and mother-in-law, Melania Trump. They did not shake hands with the Clinton family.