50First, it cannot be excluded that Tirrenia was, as TDM contends, in competition with undertakings from other Member States on the domestic routes concerned, which it is for the national court to determine. Second, it cannot be excluded either that it was in competition with such undertakings on international routes and that, in the absence of any separate accounting for its various activities, there was a risk of cross-subsidisation, that is to say, in the present case, a risk that the revenue from its cabotage activity which received the subsidies at issue in the main proceedings was used for the benefit of activities carried on by it on its international routes, which it is also for the national court to determine.