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.

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.