The final five candidates in the Conservative leadership race have clashed over their tax plans in a fiery first TV debate.

While former Chancellor Rishi Sunak dismissed tax cut pledges by his rivals as an “unfunded spree of borrowing and more debt”, Foreign Secretary Liz Truss hit back, saying: “You cannot tax your way to growth.”

Penny Mordaunt said “people need help now” and without a change in the tax burden, the UK will become “one of the most uncompetitive nations” by next April.

But Mr Sunak insisted he had been right to take the “difficult decisions” in the Treasury, such as increasing National Insurance to pay for health and social care, and promising reductions now was a “fairy tale”.

Politics Hub: ‘Is Johnson an honest man?’ – Tory candidates react to questions in first TV debate

In the 90 minute debate on Channel 4, the runners were also asked the yes or no question of if Boris Johnson was an honest man.

While most gave longer answers than requested, Kemi Badenoch said “sometimes”, while Tom Tugendhat flatly said “no”.

It was the first of three TV debates the competitors will face in the race to become the next Tory leader and the next prime minister of the UK.

The next will fall on Sunday evening on ITV, while Sky News will host its own debate at 8pm on Tuesday, hosted by Kay Burley.

The candidates will be whittled down further on Monday, when a third round of voting will take place.

The final two leadership hopefuls will emerge by the end of next week and then face a summer of hustings – with Conservative Party members getting the chance to decide who should become the next prime minister.

A winner will be announced on 5 September.

The exchanges became the most tense during tonight’s debate when they were asked about their tax plans, which has been a running issue throughout the contest so far.

Mr Sunak – who resigned as chancellor last week – stood by his record in the Treasury, saying rather than focusing on tax, “inflation is the enemy that makes everyone poorer”.

He added: “I don’t think the responsible thing to do right now is launch into some unfunded spree of borrowing and more debt, that will just make inflation worse, it will make the problem longer.”

But Ms Truss, who has pledged to stop the planned rise in corporation tax and pause green levies to reduce the tax burden, blamed the Bank of England for the current record rates of inflation.

“We have inflation because of our monetary policy, that we haven’t been tough enough on the monetary supply, that’s the way that I would address that issue.”

But Mr Sunak replied: “Borrowing your way out of inflation isn’t a plan, it’s a fairy tale.”

Many of the candidates who had voted for the rise in NI, including Ms Truss, promised to scrap it if they got into power, but Mr Sunak insisted he would stand by the measure, despite it not being as “politically convenient” conviction.

But Mr Tugendhat said the ex-chancellor only brought it in “because the boss wanted it”, and stuck by his decision as the only member of the panel to vote against it.

On overall tax policy, he said he would like the public to “keep more” of their money, but “public services are incredibly important to all of us” and they needed funding.