Liz Truss claims her economic agenda of tax cuts and public spending will revitalise the UK economy, but it is not just her rival prime ministerial candidate Rishi Sunak arguing that the measures will be self-defeating.

Economists have lined up to warn that her £30bn package – including the reversal of this year’s national insurance rise, the suspension of green levies on power bills, and the cancellation of a sharp rise in corporation tax in 2023 – will increase inflation and leave the government with higher debt bills.

The foreign secretary and frontrunner in the race for the Tory leadership has criticised the Treasury’s economic record during her opponent’s time as chancellor, saying it has been timid and “contractionary” when it should have been promoting growth.

Citing other European countries that have spent more money supporting households hit by the cost of living crisis, Truss has said she would allow people to keep more of their own money by taxing less. She has also touted a carer’s allowance and pushing defence spending up to 3% of GDP – amounting to an extra £86bn over the next five years – as ways to help the UK avoid a recession.

Meanwhile, the Bank of England has come under attack from Truss and her allies because she claims looser government spending should have a counterweight in tighter policy on controlling the money supply.

Harking back to Margaret Thatcher’s stance in 1979, Truss believes inflation is partly the result of cheap borrowing fostered by the central bank, so tighter monetary policy would limit rising prices. Last weekend she said the government should “look again” at the Bank’s mandate “to make sure it is tough enough on inflation”.

At the moment the BoE is independent and arrives at its own policies to bring down inflation to a 2% target. Truss is likely to cause consternation in financial markets if she seeks to meddle in the central bank’s decision-making.

Nick Macpherson, the former Treasury permanent secretary, described the tax-cutting proposals of Sunak’s rival Tory candidates, including Truss, as “less the heirs to Margaret Thatcher; more the disciples of Recep [Tayyip] Erdoğan”.

Turkey’s president has sacked more than five central bank bosses because they failed to pursue his chosen interest rate policy. It has left the country with a near-80% inflation rate and a currency worth 90% less than when Erdoğan began running the country almost 20 years ago.

Ben Nabarro, UK economist at Citi, said: “Liz Truss’ policy platform poses the greatest risk from an economic perspective with an unseemly combination of pro-cyclical tax cuts and institutional disruption.”

Robert Joyce of the Institute for Fiscal Studies thinktank warned that her £30bn worth of pledges would have implications beyond the tax system that remain unclear.

But one thing is for sure: “they will mean higher borrowing or less public spending, or some combination”, so vast swathes of Whitehall and welfare spending will need to come under the hammer. “In the end, lower taxes do mean lower spending.”

Truss’s strategy does have some backing, however. The economist Gerard Lyons emerged as a potential supporter after he told the BBC Radio 4’s World at One: “We need tighter monetary policy to tackle inflation and looser fiscal policy to promote growth.”

He dismissed claims that targeted tax cuts would be inflationary and self-defeating, saying a sharp reduction in fuel duty by cutting the green levy would push down transport costs.

Truss also cited Patrick Minford as an economist who approved her approach. The Cardiff University academic came to prominence ahead of the Brexit referendum, which he claimed could generate £135bn in extra income for the UK. Last year the government’s independent forecasters at the Office for Budget Responsibility assessed it would cost around £80bn in lost income.

The OBR also warned this month that tax cuts rarely pay for themselves. Worse for Truss and her proposals, it said, Britain’s public finances were on an “unsustainable” long-term path, with a debt burden that could more than treble without further tax rises to cover the mounting cost of an ageing population and falling fuel duties.