The High Court has allowed U.K. insurance group Watchstone, formerly known as Quindell, to bring a counterclaim against Slater & Gordon, in a longstanding dispute over the law firm’s £637 million acquisition of the group’s professional services division.

In seeking permission to amend its defence and bring a counterclaim, Watchstone accused the U.K. arm of Slater & Gordon of breaching its contractual obligations, and of breaching confidence by obtaining confidential information on then-named Quindell by way of “unlawful means conspiracy”, which caused it to suffer “significant loss”, according to the judgment.