More than 50 top charities and campaigners have demanded a £20-a-week Universal Credit rise is made permanent.

The new coalition has written to Chancellor Rishi Sunak warning 700,000 more people - including 300,000 children - will plunge into poverty “at a stroke” if the one-year boost ends as planned in April 2021.

The organisations, including Oxfam, Scope, Shelter, Centrepoint, Rethink Mental Illness and the Trusell Trust, add: “We are therefore urging you to make the uplift permanent and stop families being cut adrift whilst they need help to stay afloat.”

Universal Credit rates were raised by £1,040 a year in April to help people cope with the pandemic.

The charities are also calling for the boost to be extended to older ’legacy’ benefits, more than a million of whom are sick or disabled.

The coalition is made up of children’s charities, food bank providers, housing organisations and benefit and debt advisors.

The new coalition has written to Chancellor Rishi Sunak

It has highlighted research by the Joseph Rowntree Foundation think tank warning 16million people will be hit if UC is cut in April.

The think tank says 700,000 would be pulled into poverty, and 500,000 already in poverty would enter "deep poverty".

The coalition sent the letter after the Chancellor admitted non-"viable" jobs will be lost when furlough ends on October 31.

They write: "Your statement last week made clear that many families will see job losses over the months to come, and even those whose jobs are protected through the Job Support Scheme will see income cuts.

"Even the most optimistic forecasts expect unemployment to surge and remain high for some time to come."

Department for Work and Pensions ministers have so far refused to say if the £20-a-week rise will be made permanent.

Instead they have pointed to Mr Sunak, saying any decision will need to come at a "fiscal event".

That could leave benefit claimants waiting months for clarity, because plans for a Budget this autumn have been scrapped. A Budget is now expected in the Spring.