“The charges are being dropped with no fines or penalties. They’ve had a long time to wait to be told your case is ridiculous,” Stirling said.

[2015] Conrad Clitheroe, 53, and his friends Gary Cooper, 45, and expatriate Neil Munro were detained in February after being spotted by an off-duty police officer taking notes near Fujairah airport, about 80 miles from Dubai.

The men were taken to a police station where they signed an Arabic document apologising and promising not to plane-spot in the country again, before they were moved to a higher-security prison.

Radha Stirling, CEO and founder of Detained in Dubai, which intervened in the case, said charges of espionage against the trio had been dropped at the supreme court in Abu Dhabi.

The men were due to be released on Monday, she said.