Heath Lambert has won an injunction against three former members of its property team who defected to Willis, according to industry sources.
The injunction has banned former senior members of Heath Lambert - Adrian Hastie, Dean Gallagher and Ty Harris - from "working for or with any company or person without the consent of Heath Lambert" the source said.
The injunction also banned them from "contacting or dealing with any person, or company with a view to soliciting or encouraging business away from Heath Lambert without prior consent".
It is also understood that the three property specialists must provide Heath Lambert with full details of every client and person they have spoken with or dealt with subsequent to handing in their notices to Heath Lambert. They must also pay costs relating to the injunction.
The injunction will remain in force until the case comes to trial, expected to be in June.
Last month, Willis announced the recruitment of the Heath Lambert property team, including former Heath Lambert property portfolio managing director John Dilley who is on gardening leave for 12 months.
The source said: "They paid a fortune to buy a team and have nothing to show for it but a bunch of junior staff and a big salary bill."
A spokesman for Willis said it would be "inappropriate" to comment as it is still an open matter.
Heath Lambert declined to comment.