The town hall’s housing chief has warned that 3,000 Islington residents will be hit by another wave of benefit cuts.

From next April, all those the government decides are under-occupying properties will have their housing benefit cut by up to 25 per cent.

Even those with just one extra bedroom will have their rent income cut by 14 per cent, and Islington Council estimates that several thousand households could be negatively affected.

Under government guidelines on occupation, all children, regardless of sex, have to share a room until they are ten. Same-sex siblings must share until they are 16.

The council says that if everyone agreed to downsize, there aren’t enough properties to accommodate them.

Labour councillor James Murray, executive member for housing and development, said: “These cuts are very fast and very harsh – the impact could be huge. The scale of them could have a very significant effect, particularly as this is just one of a wave of attacks by the government. The definition of how many rooms you need is really strict and you could end up with two 16-year-old lads sharing a room.

“Even if everyone wanted to downsize, you could get two years of transfers in just one day. I have written to the Work and Pensions Secretary, Iain Duncan Smith, asking him to phase the cuts, or make exemptions if the properties aren’t available. The cuts could be really damaging and cause hardship.”

A spokeswoman for the Department for Work and Pensions said: ‘‘It’s not fair for people to continue to live in homes that are too large for their needs when there were five million households on the waiting list.’’

The department has given �190millions to councils in Great Britain to ease the impact of welfare reforms.