The iron rule of Conservative deficit targets is that once set they are missed. There is no sign that Philip Hammond will succeed where George Osborne failed. As the Times reported this week, the Chancellor may announce in his autumn Budget that the deadline for eliminating the deficit has been extended from 2025 to 2027 (having already been extended from 2022).

The loss of the Tories' majority has forced them to abandon planned cuts such as the abolition of the state pension triple lock, universal winter fuel payments and free primary school meals, and to gift £1bn to the DUP, while the rise in inflation has increased the cost of servicing the UK's £1.6 trillion debt (80.9 per cent of GDP). Two years after Osborne aimed to achieve a surplus, government borrowing is forecast to rise from £46bn last year to £58bn this year.

Britain's deficit (which peaked at £153bn in 2009-10) was the original and pre-eminent justification for cuts. Unless borrowing was largely eliminated by 2015, George Osborne warned, Britain's public finances would become unsustainable. But as time has passed, this argument has become progressively weaker. The UK has cumulatively borrowed £200bn more than promised by Osborne, yet apocalypse has been averted. With its low borrowing costs, an independent currency and a lender of last resort (the Bank of England), the UK is able to tolerate consistent deficits

In defiance of all this, Osborne vowed to achieve a budget surplus by 2019-20 (a goal achieved by the UK in just 12 years since 1948). The Conservatives made the target in the knowledge that promised tax cuts and spending increases would make it almost impossible to attain – but it was a political weapon with which to wound Labour.

Brexit, however, forced the Tories to disarm. Mindful of the economic instability to come, Hammond postponed the surplus target to 2025 - a target now endangered itself Britain's past and future borrowing levels mean the deficit has lost its political potency.

In these circumstances, it is unsurprising that voters are increasingly inclined to look for full-scale alternatives. Labour has remade itself as an unambiguously anti-austerity party and Britain's public realm is frayed from seven years of cuts: overburdened schools and hospitals, dilapidated infrastructure, potholed roads, uncollected bins.

Having abandoned Osborne's political strategy, the Tories have yet to find an alternative (beyond the divisive and Sisyphean task of delivering Brexit). Both Hammond and Theresa May are too fiscally cautious to embrace the Keynesian approach long urged by economists. Though austerity has been moderated, signature measures such as the public sector pay cap and the benefits freeze endure.

In his recent Mansion House speech, Hammond conceded that voters were impatient "after seven years of hard slog” but vowed to "make anew the case" for austerity. But other Tories believe they need to stop fighting a losing battle. The Conservatives' historic strength has been their adaptability. Depending on circumstance, they have been Europhile and Europhobic, statist and laissez-faire, isolationist and interventionist. If the Tories are to retain power, yet another metamorphosis may be needed: from austerity to investment.