Barnet Council have promised an investigation into how the wrong electoral registration lists were sent to polling station yesterday.
The error meant some voters without polling cards were turned away and unable to vote in the elections. The council did arrange for people to make an emergency proxy vote if they were unable to return to polling stations in person.
Andrew Travers, Barnet and Camden constituency returning officer, said: 'Taking part in the democratic process is a fundamental right for our residents and the main focus this morning was to resolve the situation as soon as possible.
'We will fully investigate the cause of the problems that have arisen. I would like to apologise to everyone who experienced problems with voting in Barnet today.'
The council could face having to re-run the elections following the problems. Sophie Walker, the Women's Equality Party mayoral candidate, said: 'Women first got the vote 100 years ago and there are women today who have been unable to vote.
'We will be pursuing a complaint.'