Google are having to change their domain in the UK due to ongoing legal issues over the gmail name. They have FAQ page up, stating that they are no longer issuing gmail accounts, but have switched to googlemail.com. The question about whether I will have to change domain remains open:
# What if I’m a UK user who already has a Gmail address? Will that address ever change?
Unfortunately, we don’t know. We would love to say that your address will always remain the same. But the trademark issue is still unsettled, and unfortunately, we cannot predict what the other party or the courts might do here. You can always use your same username with an @googlemail.com address to avoid this issue later on. But trust that we will do the best we can to make sure your email address won’t ever have to change.
# What if I’m a UK user who already has a Gmail address? Will I also need to change that address?
No, this change doesn’t affect existing Gmail addresses. For now, our plan is only to issue @googlemail.com addresses to new users. Trust that we will do the best we can to offer all our users a reliable and consistent email experience.