In his November Spending Review the chancellor announced that ‘housing benefit in the social sector will be capped at the relevant local housing allowance’.

For many council and housing associations, this will not cause any immediate concern as their rents for general housing are lower than the local housing allowance level.

But with one short, sweeping sentence he put at risk almost all supported and sheltered housing for the frail elderly, the homeless, young adults leaving care, those suffering with dementia, people with mental illness or learning disabilities, veterans and women fleeing domestic violence.

Specialist sheltered and supported housing schemes that provide extra support for tenants have much higher housing costs, with their higher rents and service charges often covered by housing benefit.

According to the National Housing Federation, this means that nearly half all such housing schemes face closure – more than 150,000 homes. A survey by Inside Housing magazine found that one in four supported housing providers are set to close everything, while 19 out of 20 say they will close some of their supported accommodation.

Last week I called a debate in the House of Commons to hold ministers to account for their decision, give voice to those that will be affected and argue that such supported housing must be exempt from these crude across-the-board cuts.

Before doing so, I wrote to MPs and council leaders of all parties to alert them to this serious problem and to this ask for their support. I received a big response. This is not a party political issue, but something that concerns all of those who want to protect vital accommodation for the elderly and vulnerable in their areas.

It is councils who run or help fund much of this accommodation, and often have ultimate responsibility for the people who live in it, who must be on the frontline of this campaign to make the Government think again.

The fact is since I revealed the scale of the problem before Christmas, the Government has given no good justification for these cuts.

First we were told ‘this is unnecessary scaremongering’ where in fact, all I have done is to give voice to the warnings from those who have the evidence and will have to manage the consequences. Not just councils and housing associations across the country but organisations the British public trust and respect, including Age UK, Mencap, St Mungo’s and Women’s Aid.

Second, ministers said ‘nothing will change until 2018’. In fact, the cut applies to new tenancies from April this year, so the problem is immediate. Landlords will be wary of signing new tenancies if they think tenants cannot pay the rent in two years’ time. My local housing association, South Yorkshire Housing, has been clear: consultation on scheme closures could need to begin within a matter of weeks because so many of the residents will be so hard to house in alternative accommodation.

What’s more, we know the plan for these cuts has already meant much-needed development of new supported housing has been scrapped or mothballed. The National Housing Federation says building work on an estimated 2,400 new specialist homes has already been cancelled. Golden Lane Housing – Mencap’s housing arm – tells me they had plans for £100m investment over the next five years in supported housing across England, but it has been stopped.

Third, the Government says ‘additional discretionary housing payment funding will be made available to local authorities, to protect the most vulnerable, including those in supported housing’. Councils know better than anyone that this fund is short-term and overstretched and discretionary housing payments will simply not be able to deal with the shortfalls tenants will face, which will be large and on-going. And while the Spending Review report scores the cost of the chancellor’s housing benefit cut at £515m, the Government proposed to top up the discretionary housing payments fund by only £70m.

I happen to agree with the prime minister, who said before the election: ‘The test of a good society is you look after the elderly, the frail, the vulnerable, the poorest in our society.’

It’s now time for councils to join the campaign to help hold him to that pledge – and to exempt supported housing from these crude housing benefit cuts.

John Healey MP is Labour’s shadow cabinet minister for housing and planning