He responded on CNBC: “I suspect that’s the case, before the pandemic public finances looked pretty challenging, what will really determine the size of the tax increase we need going forward is how full is the economic recovery, how much we will be able to bounce back.
“And secondly, what more do we want to spend on public services as a result of the pandemic – such as improvements to social care or increased capacity in the NHS.
“If we choose those things and if the economy doesn’t fully bounce back, big tax rises will be needed. I wouldn’t be surprised to see VAT or income tax rates go up to bring the deficit down.”
Pensions director at Aegon, Steven Cameron, said there may be another Budget this year in which hikes could be issued, including a potential removal of another manifesto pledge.
He told Express.co.uk earlier this month that the pension triple lock could be ditched.
Mr Cameron said: “We are anticipating another Budget before the year ends, so we think there’s every chance there will be another Budget maybe in November.
“Sunak did say that it is too early to to make detailed fiscal policy announcements. We still don’t know the full costs of furlough and other support schemes. We still don’t know the full impact on the economy.
“I do expect he will be making further changes which could be of a detailed and wide-ranging nature. We shouldn’t assume that because he didn’t announce things, he won’t be thinking about them as longer term measures.
“We have got a manifesto commitment on the pension triple lock and tax triple lock, with all of these locks he’s got more locks than Houdini to grapple with.
“At some point, the Government might decide we have to be open with the public and say, ‘If we stick with these manifesto commitment we will have too many restrictions to do what is right to do.’
“He’s not done it so far, but in future there may come a time when he has to level with the public.”
Mr Emmerson also highlighted a difficult balancing act that Mr Sunak will have to grapple with to ensure the UK economy recovers quickly.
The easing of support schemes will prove crucial, he said.
The economist added: “I think that it’s pretty clear that the Government is going to be borrowing large sums of money over the next few months as the economy is still in lockdown.
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“The Chancellor is going to have to extend his support schemes such as the furlough scheme and for the self-employed.
“I think the really difficult call for Mr Sunak is how you ease out of that, how fast you withdraw that kind of support.
“If for example you withdraw the furlough scheme too quickly, it means viable jobs that you have been supporting for all of the last year could end up terminated.
“Phase it out to slowly, and you will be propping up people in jobs that don’t exist and hindering the adjustments the economy needs to make.”