McLaren are seeking legal advice after Formula One champions Red Bull announced the appointment of an aerodynamics expert their rivals say it contracted to them.
Red Bull said Dan Fallows has been appointed head of aerodynamics, replacing McLaren-bound Peter Prodromou who is now on 'gardening leave'.
The statement drew a swift response from McLaren, who announced at their car launch in January that Fallows had joined along with Prodromou.
McLaren says Fallows has a legally binding contract with them and the matter is now in the hands of their lawyers.
Red Bull said Fallows had left them last year after working as aerodynamics team leader but had returned and was starting his new job with immediate effect.
McLaren announced last October that Prodromou would be joining them but Red Bull, constructors' champions for the past four years, were determined to hold the much sought-after Briton to his contract.
Red Bull have won the last four constructors' and drivers' championships, with Sebastian Vettel triumphant in the last nine races of 2013, but have started the season chasing dominant Mercedes.