A paragliding protester has flown 'within 45 metres' of Donald Trump as thousands took to the streets throughout the United Kingdom in opposition to the US President.

The Greenpeace paraglider swooped down towards the former Celebrity Apprentice host as he was enjoying the view from his Turnberry golf resort, reported ITV News' Martin Geissler.

Flying a sign reading 'Trump: Well below par', the protester reportedly circled the resort - past the president's team of snipers - before being pursued by police while Trump was escorted inside.

A Greenpeace spokesperson criticised Trump's stance on climate change, including his pulling out of the Paris climate accord and overturning an Obama clean power plan.

"He is, simply, the worst president ever. That's why we flew over him with a message branding him well below bar."

Greenpeace says it had informed police and local air traffic control of the paragliding protest prior to it taking place.

The demonstration marked the end of a day of protests, with tens of thousands coming out from across the UK and marching against a US President they say is racist and sexist.