Why McLaren won't get latest spec Mercedes engine for British GP

McLaren will not receive the latest specification Mercedes power unit for the British Grand Prix, despite other customer teams being set to introduce it. Mercedes began rolling out the new engines in Austria, with works drivers George Russell and Kimi Antonelli the first recipients; the update brings reliability improvements rather than outright performance gains, though fresher engines with less mileage provide a minor power benefit. McLaren must wait at least one more race before taking delivery of the upgraded units.