For example, you might think that having a few employees working from their homes in the UK doesn't create a UK corporation tax risk, but it could do.

Yes, and helpfully, because of developments in the last year, we now have more clarity on the question of whether a home office creates a permanent establishment.

There's now a 50% working time threshold test, which says that where an employee spends less than half their total working time in a 12 month period from a UK location, that location is presumed not to be a fixed establishment PE of the overseas company.

However, where these employees spend more than half of their working time in the UK, and there is a commercial reason for that UK presence, such as holding regular meetings with clients or suppliers, or to be on the same time zone as customers, then a PE is likely to be created.

This is a common pitfall.

In practice, that can mean that the UK PE is attributed a positive arms length return subject to UK corporation tax that cannot be sheltered with overseas losses.

Even if you incorporate a UK subsidiary, you still need to be mindful of tax risk when pricing intercompany services.

The UK company should price its services as if it were dealing at arms length based on the functions it performs, assets it uses and risks it assumes.