'It feels unrealistic' Why Ruth Curtice is ready to tell Labour hard truths on tax

'She clearly has to fix the problem. I think it's one thing to come back twice. We don't want to be here a third time."

- Heather Stewart

Bluntness served Ruth Curtice well in her former life as a senior Treasury official. These days, she deploys it publicly, as chief executive of the Resolution Foundation urging Rachel Reeves to think the unthinkable before November's crunch budget.

In the course of half an hour's conversation in her bright white Westminster office, Curtice says the chancellor must be ready to ditch Labour's manifesto tax pledges; scrap the pensions triple lock; lift the two-child limit on benefits - and forget the idea that a new wealth tax is the answer to anything.

As a longtime civil servant, the 41-year-old Curtice served nine different chancellors and rose to be the Treasury's director of fiscal policy, before crossing St James's Park earlier this year to run arguably the UK's most influential thinktank.

She stresses its non-partisan nature, and impact on past policies, including George Osborne's "national living wage" - but there is no denying its intimate links to the current Labour regime.

Curtice's predecessor, Torsten Bell, is the pensions minister, recently handed a key role in thrashing out plans for the budget. The newbie Treasury minister Dan Tomlinson is a former Resolution Foundation economist. Richard Hughes passed through en route from the Treasury to the highly influential post of director of the Office for Budget Responsibility (OBR). Keir Starmer's new economic adviser, Minouche Shafik, co-chaired the thinktank's weighty Economy 2030 commission. The appointments have triggered accusations that a "leftwing cabal" has taken over the Treasury.

Curtice says the thinktank has "no affiliation" with Labour, and that, of the seven Conservative chancellors she worked with, "lots of them care about exactly the group that Resolution care about".