To make sure every adult in your household is registered to vote check the names on the letter from Lambeth Electoral Register team. If you didn’t get a letter or are not listed in the letter its easiest to register online at https://www.gov.uk/register-to-vote
All British, Commonwealth & European citizens are entitled to register to vote.
Having your name on the electoral roll also helps with things such as credit checks. So even if you move frequently its worth registering to vote at your new address. And be ready for any sudden general election!
The next elections are on Thursday 3rd May 2018 for the council