Comment by chippiewill

A variety of things could happen:

- Employees become accountable for their company's actions - Wikimedia could be blocked - Other kinds of sanctions (e.g. financial ones) could be levied somehow

In practice what will likely happen is Wikimedia will comply: either by blocking the UK entirely, making adjustments to be compliant with UK legislation (e.g. by making their sites read-only for UK-users - probably the most extreme outcome that's likely to occur), or the as-yet unannounced Ofcom regulations they've preemptively appealed actually won't apply to Wikimedia anyway (or will be very light touch).