Obviously exact orders will depend on the estimate and how fair it is to use 2019 figures and then subtract the UK from them.
But however you slice it, the UK is not pocket change. Maybe smaller companies can ignore all but the largest three, but I doubt it.
It's more likely that the UK will prefer a more liberal market, and for that reason their laws will be a little ignored - they won't enforce them and will forever be planning their repeal even if they never quite get there.