I moved to the UK in 2010. I lamented to a colleague that the most frustrating thing about being an immigrant was not being able to vote.
My friend put me straight. Commonwealth citizens legally resident in the UK (regardless of how long we've been here) are allowed to vote. You just have to register.
Are you Canadian? Australian? Indian? Nigerian? If you're allowed to live here, you're allowed to vote.
Today's your last day to register.
https://www.gov.uk/register-to-vote