Can US wii games be made complatible with UK consoles

Yes, but it requires to modify the console's hardware by adding a chip that bypasses some built in security systems. In some countries these chips are illegal (at least Australia), but in some they are perfectly legal.
Nintendo prohibits the users from modifying their consoles, thus adding the mod chip is a violation of user agreement. By this Nintendo has the right to deny services from you. Warranty doesn't include damage done to the console by an update which is not compatible with your console if you have added the mod chip.

Microsoft has banned users from Microsoft Live network if they found that the players are using a modded console. Nintendo has yet to do anything, but such actions are allowed due to user breaking the user agreement.