Almost 800,000 homes will become off limits to benefit claimants relying on housing benefit to pay the rent because of government cuts to the local housing allowance that begin in January, according to research by the Chartered Institute of Housing and the Guardian.

According to the report, for the first time more people on benefits will be chasing homes than the market currently provides. The study shows in many parts of the country there will be thousands more welfare claimants than there are properties that can be afforded by benefits alone.

The result is that in many urban areas there will not be enough inexpensive homes to rent for those claiming local housing allowance. The problem is most acute in central London where in two of the country’s richest boroughs: Westminster and Kensington and Chelsea, more than 35,000 homes will at a stroke become unaffordable to those attempting to live on housing benefit.

It’s unlikely that the poor can migrate to other parts of the capital: in east London Newham there are twice as many claimants as there are low cost homes. There’s no room in the suburbs either. In Croyden 17,000 people will be chasing the 10,000 properties that can be paid for with local housing allowance levels.

The effect is not just in the south east. Before 2012 Birmingham had more than 37,000 homes with rents that could be paid for by housing benefit. Now, 34,500 benefit claimants will be chasing just 23000 low-cost houses. On the Mersey, Liverpool’s 21,000 people collecting the allowance will only be able to afford 12,000 homes in the city.

Take a look at the interactive map on the Guardian datablog to look at the figures for your area. The data can be downloaded too.