"I don't know when this £26,000 cap is coming in. And if it's connected to UC. And even if it includes Housing Benefit."
The cap most definitely does include HB.
Any families who are on £26,000 are most likely living in a part of the country with expensive rents.
FWIW it really annoys me when people say things like "why should people on benefits get to live in posh areas, I can't afford it, why should they?"
We're not just talking about posh areas, we're talking about most of London. The bit of London I grew up in has long been a deprived area, yet rents there will easily take a family over the cap.
It's social engineering on a grand scale as it amounts to a mass removal of the poor from London and much of the South East (as well as other city centres in the UK).
Camden Council for example recently announced that welfare cuts were forcing them to shift of 2,816 adults and children to areas up to 200 miles away with lower housing rents.
"Camden council said that it would shortly be contacting 761 households, comprising 2,816 adults and children, because the coalition's benefit cap ? which limits total welfare payments to £500 a week for families ? will mean that they will be unable to afford their current accommodation or any other home in the south-east.
The Labour-controlled council warns that the majority of these families have three children and, once the cap is imposed this summer, will need to find on average an additional £90 a week for rent to remain in their homes ? which means "sadly the only long-term solution for some households will be to move".
The local authority says it has been forced to look as far afield as Bradford, Birmingham and Leicester and warns that 900 schoolchildren ? more than one child for each class as an average across the borough's schools ? face having their education disrupted by the move."
This breaking up of communities is criminal IMO 
Who does it benefit to rip families from their roots and dump them in poorer areas with fewer prospects? It makes all of society poorer IMO.
How are people meant to rely on the "Big Society" if they're moved away from their informal network of support of friends and family? Unless perhaps the "Big Society" idea was all spin, oh wait ...