Donald Trump refuses to prove he is not taking a salary, despite promise to do so

White House and Treasury fail to provide evidence for claim President is giving his $400,000-a-year income to charity

Donald Trump is the richest President in the history of the United States, (Scott Olson/Getty Images)

Donald Trump has ignored requests for proof he is donating his $400,000 annual salary to charity, despite promising during his campaign to waive the pay package.

Inquiries about the promise placed at the White House, the Treasury Department and the Office of Personnel by MSNBC were ignored or waved away.

Likewise, The Independent's request for clarification with the office of White House Press Secretary Sean Spicer is yet to see a response.

If he is in fact drawing the salary, Mr Trump would have received his first $33,333 pay packet in January, and be pocketing another cheque on 20 March.

In a interview on CBS, conducted two days after his triumph over Hillary Clinton, the billionaire tycoon doubled down on his campaign commitment to draw "no salary".

He said: "I think have to by law take $1, so I'll take $1 a year... no, I'm not going to take the salary. I'm not taking it."

Under Constitutional law, the President must be paid the salary by law, which "shall neither be increased nor diminished during the period for which he shall have been elected".

As such, a White House spokesperson subsequently suggested he would be drawing a wage but then donating it.

"He is required to get a paycheck but will be giving it back to [the] Treasury or donating," Sarah Huckabee Sanders told the website Politifact. But to date, no evidence has been provided for any of these claims.

Past Presidents to eschew a salary include Herbert Hoover, John F Kennedy, and the country's first ever Head of State, George Washington.

In today's money, those men were worth $82 million, $100 million and $580 million respectively, ranking them all among the 10 richest presidents of all time.

But all these fortunes are dwarfed by Mr Trump's. Though estimates vary wildly, he is thought to be worth some $3.7 billion.

That means the Presidential salary is worth just 0.01 per cent of his total fortune.