The Benefit cap was introduced from the 15 July 2013. The cap limits the amount of benefit people who were able to work could receive while not working. This does not apply to people aged 65 and over.
The amount your household gets from some benefits might go down to make sure you do not get more than the cap limit. View the current benefit cap limits (external link)
If you struggle to pay your rent due to the Benefit Cap then you can apply for Discretionary Housing Payment