Non-UK structures can protect you from UK tax.
The UK tax system has a defined structural basis. In general, UK resident taxpayers are taxable on their worldwide income and gains, whereas taxpayers who are not UK resident are only subject to UK tax on their UK income. A non-UK structure can take advantage of this territoriality for UK tax purposes.
It is possible to use foreign companies for overseas aspects of a business so as to keep business profits outside UK corporation tax.
Foreign trusts and pension schemes can hold non-UK assets outside the scope of UK capital gains tax and inheritance tax, and may not be subject to the same limits that a UK pension scheme has, allowing a greater retirement fund to be built up.