Vote 2011: Londoners go to the polls in AV referendum
Polling stations have opened in London as part of a UK referendum on whether to change the way MPs are elected.
The public are being asked if they want to keep the first-past-the-post system for Westminster elections or switch to the alternative vote (AV).
Under an AV system, instead of just voting for one candidate voters could rank candidates in order of preference.
Polls opened at 0700 BST and will close at 2200 BST. Results are expected after 2100 BST on Friday.
Counting is due to start at 1600 BST on Friday.