A Council spokesperson said:
Users of the Royal Borough of Greenwich’s online Council Tax account may have received an automated email today, Friday 5 December, asking them to change their password. We would like to reassure users that the email did come from the Royal Borough of Greenwich, but it was issued in error. Users may need to reset their passwords and if users have done so already their data is safe. It is good practice to update passwords regularly using strong, unique passwords and avoiding the same passwords across multiple accounts.
We’re sorry for any confusion or concern this may have caused.