Disabled adults and families with disabled children are challenging the legality of the Government's so-called "bedroom tax", arguing that it unlawfully discriminates against them.
New housing benefit regulations have led to reductions in benefit payments to tenants in the social housing sector assessed to be under-occupying their accommodation.
Lawyers in 10 cases at London's High Court are seeking a ruling that the regulations, introduced on April 1, "unjustifiably discriminate against housing benefit claimants who are disabled or care for disabled family members".
More top news
A man has been rescued by firefighters - after getting his head stuck inside a washing machine.
Late-running passengers who attempt to pass through security with less than 30 minutes before their flight departs will now be stopped.
A Ukrainian pilot who spent two years in prison in Russia has been sworn into national parliament after being released last week.