Nopes, only UK registered aircraft flying under a UK AOC are required to enforce it.
Bit like how Ryanair although with numerous bases all around Europe fly Irish registered aircraft and are trained and follow Irish aviation law!
I’m not making it up ya know!!!!
Sorry hate quoting wiki but here ya are…
“A 2000 study by the British Civil Aviation Authority found that a mobile phone, when used near the cockpit or other avionics equipment location, will exceed safety levels for older equipment (compliant with 1984 standards). Such equipment is still in use, even in new aircraft. Therefore, the report concludes, the current policy, which restricts the use of mobile phones on all aircraft while the engines are running, should remain in force.”
And the crossair bit is relevant, it provides a background to the ban of mobile phones on aircraft and the belief (rightly or wrongly) that they cause interference!