The man was arrested on Tuesday after a drone was flown near Windsor Castle the day before US President Donald Trump's state visit, the Associated Press reports.

Thames Valley Police said the man was arrested on suspicion of violating airspace restrictions, which are part of heightened security plans ahead of Trump's visit, which will include a lavish banquet at the castle on Wednesday hosted by King Charles III.

The 37-year-old London suburban resident is in custody after being arrested in Windsor Great Park.

Flight restrictions are in place until Thursday in Windsor, as well as in Chequers, the country estate where Prime Minister Keir Starmer will host Trump.

Thames Valley Police said it was monitoring Windsor from the air, deploying armed officers to the streets and patrolling the River Thames to provide additional security during the visit.