There is further evidence that Donald Trump’s occupation of the Oval Office has had a negative impact on his business empire, with new research showing that average room rates have fallen by as much as 63 per cent at all but one of his 13 hotels.

Hardest hit was Trump Las Vegas. The average cost of a two-night stay in a standard double room during January 2017, just before his inauguration, was priced at £637, according to analysis by FairFX, the currency provider. But a two-night break in January 2018, one year on, can be secured for just £237.

At Trump Turnberry, his Ayrshire golf hotel, the average cost of a two-night stay has fallen by 57 per cent, from £498 to £215, while steep drops have also been found for stays at Trump Doral in Miami (down 53 per cent), Trump Washington DC (down 52 per cent), Trump Vancouver (down 48 per cent), and Trump New York (down 32 per cent). Only the president’s Irish hotel, Trump Doonbeg, has seen a rise in rates, from £334 to £357.

Rates for the premium rooms at his portfolio of properties have also fallen. A two-night stay in the executive suite at Trump Panama, for example, was priced at £3,129 during January 2017, but during January 2018 it could be yours for only £814.

While it conceded that there were other factors at play, FairFX suggested the falling prices were also indicative of a widespread fall in demand – with travellers apparently put off by Trump’s policies.

“One year after Trump’s inauguration, prices for a weekend in one of his hotels have for the most part decreased,” said Ian Strafford-Taylor, FairFX CEO. “While big events, like the inauguration in Washington, will usually cause prices to rise in that city for a particular weekend, the decreases in other places suggest that it doesn’t necessarily pay to be president.”

Nick Trend, Telegraph Travel’s consumer editor, added: “Like airfares, rooms rates are not fixed - they are determined by supply and demand and can change from day by day. Hotels cut them when sales are weak, so a drop in average room rates must reflect a fall in demand for Trump hotels.

The Trump Turnberry's Ailsa golf course Credit: 2016 Getty Images/David Cannon

“Several factors may be at play. The strong dollar has reduced tourism to the US generally, for example. But there have been falls in his hotels in Scotland and Vancouver too, and these price cuts are so significant, that it seems likely that many potential guests have been put off by the association with the controversial policies, tweets and opinions of the current US president.”

It isn’t the only evidence that Trump’s hotels, particularly those in Democratic strongholds, such as New York, New Jersey and Illinois, have suffered since he turned his attention to politics.

In October 2016, the location-based app Foursquare, which lets its users “check in” at locations they visit, reported a fall in foot traffic to Trump-branded hotels, casinos and golf courses, of 14 per cent. The biggest dip was seen at Trump SoHo, Trump International Hotel & Tower Chicago and Trump Taj Mahal, the $1bn Atlantic City hotel that has subsequently closed its doors.

Such has been the decline in visitors at Trump SoHo that one of its restaurants, Koi, was forced to close last April.