A budget to end austerity? Only if Hammond makes the rich pay | Polly Toynbee

Theresa May's foolish promise offers an open goal for Labour if the chancellor fails to abolish tax relief for wealthy voters

How do Theresa May and Philip Hammond converse in private? I doubt he roared at her like Gordon Brown did at Tony Blair - "You've stolen my fucking budget" - even though she has. Prime ministers in a corner often do it. Blair did it from a TV sofa in 2000, panicking when a cash-starved NHS tipped into crisis: he pledged health spending would reach the EU average (an unknowable moving target). Familiar? May, facing a far worse NHS crisis, promised 20bn - and then went further. Confronting a fractious Tory conference she declared "an end to austerity" (meaning and price tag: equally unknowable).

Her Brexit conundrum of impossibilities is of her own making, drawing red lines round herself with no escape. Now she's red-lined her chancellor: he must abolish the deficit, keep debt falling, cut tax thresholds and "end austerity", just like that. Impossible, says the Institute for Fiscal Studies, the great arbiter. It will cost 19bn extra just to stand still, while still cutting another 7bn from benefits: in next Monday's budget, the public won't think that ends austerity. May's foolish promise offers never-ending open goals for Labour.

Related: Philip Hammond urged to make moves to end austerity

Related: Hammond 'would need 19bn a year to meet May's end of cuts vow'