The deadline to register for June's general election is today at 23:59. If there is a rush of people who are registering last minute, it might be extended for a day or two but otherwise, if someone doesn't register before midnight, they will not be able to vote.
I'm already registered, as are my brother and mother. We registered not long after they both moved up here to Clifton as part of changing addresses and all that. Unlike in some states in the US, where registering to vote has been made difficult by the Republicans, registering to vote here is easy as is the process of voting in itself, although we do have our share of trolls who think that voter fraud is rampant and that strict laws are needed to counter it (it isn't and they're not needed).