Mr Justice Leech has handed down judgment in Lufthansa Tecknik AG v Astronics Advanced Electronic Systems [2025] EWHC 375 (Pat).

In his 386-page judgment Leech J. decided certain points in relation to cause of action estoppel, issue estoppel and abuse of process as well as assessing infringement by equivalents. However, he also determined several points of law in relation to the requirements of causation in the context of an account of profits for patent infringement as well as offering a view in respect of others (without deciding them).

In particular, Leech J. was of the view that the “United Horseshoe” rule, by which a defendant may not rely on a non-infringing alternative, does not apply to an account of profits, and that in that respect the judgment of Laddie J in Celanese v BP Chemicals [1999] RPC 203 was wrong. Further, the Judge determined that in circumstances where the Claimant did not prove that the infringement drove the sales of the infringing product, the Court should assess the profits for which the Defendants were required to account by reference to the concept of “apportionment”. On the facts of the case the Judge apportioned the profits by reference to a licensing approach, in order to “divide the profits by reference to the relative contribution of the Patent and the other factors which generated the relevant sales”.

The Judgment can be read here.

Miles Copeland and Jeremy Heald were instructed for Astronics.