Keith O'Brien, who was employed in Dublin by Deel rival Rippling, admitted being paid €5,500 a month by Deel in return for trade secrets of his employer. He later apologised for the espionage and began cooperating with Rippling when it sued him, Deel and others.

The investigators, Mark Murran, also known as Rock Investigations, and Cliona Woods of Gotham Services, strongly deny any overt surveillance or claims of harassment and intimidation.

Both 'categorically refute' Keith O'Brien's allegations of intimidation and harassment

US headquartered Deel Inc, which allegedly recruited Dublin man Keith O'Brien to pass on trade secrets to it from his employer Rippling, also headquartered in the US, did not instruct that there be covert or intimidatory surveillance on Mr O'Brien, Mr Justice Brian Cregan was told.

An Irish payroll manager received thousands of euro in monthly payments to pass information from his own firm to a rival company

Last week, Keith O'Brien told the court he had destroyed a phone a judge had ordered him to preserve.