Jeremy Corbyn’s plans to raise a “colossal” £83billion in extra taxes to fund an unprecedented public spending spree are “simply not credible”, the Institute for Fiscal Studies has warned.

This morning the Labour leader unveiled the most expensive prospectus in British political history as he launched his manifesto with an attack on the political establishment.

In anticipation of criticism of the scale of his spending commitments he quoted Franklin D. Roosevelt, the former US president, who said: “We welcome the hate.”

The Institute for Fiscal Studies said the plans would create the biggest tax burden since World War II while the Resolution Foundation, another think tank, said the size of the state would reach a post-war high and outstrip even Germany.

Mr Corbyn announced an