The Prime Minister has said victims' lives were ruined by being taken away from the UK and coerced into marriage.
He warned that parents who force their children into an unwanted marriage will face "very tough punishments" under a new law.
The Government is making forced marriage a criminal offence, with Mr Cameron claiming the practice was "little short of slavery".
The Prime Minister added that the issue had been tolerated as a "cultural practice" for too long and the time was right to take action.
Click here for more on this story
More top news
Sunny skies from the start tomorrow, but a little cool for this time of year.
A cool night leading into a chilly start tomorrow, but it will be fairly bright.
Andrew Dodsworth is hoping that by "banking" his voice he will be able to keep some of his identity, if the condition causes his voice to go