A former ministerial adviser has questioned the Government's spending forecasts, saying the targets were ‘impossible' and ‘insane'.

Speaking at a Resolution Foundation seminar this morning, Giles Wilkes, a former adviser to business secretary Vince Cable, questioned the Government's forecasts for a budget surplus by 2019, saying estimates for departmental spending cuts over the next four years were ‘insanely wrong' and ‘imply the destruction of the state.'