Labour leader Sir Keir Starmer said he was “absolutely gutted” to have to pull out of the Budget after testing positive for Covid-19.

The leader of the opposition normally responds to the Chancellor’s statement in the Commons, but his place at the despatch box was taken by shadow chancellor Rachel Reeves.

Shadow business secretary Ed Miliband stood in for Sir Keir at Prime Minister’s Questions.

In a video posted on Twitter, the Opposition leader accused Chancellor Rishi Sunak of doing “nothing about the cost-of-living crisis” in his fiscal statement.

Sir Keir said: “I was absolutely gutted to test positive for Covid just before PMQs and just before the Budget response.

“I’m fine but it is obviously important we all follow the rules.

“But wasn’t Ed Miliband at PMQs and Rachel Reeves in the Budget response just brilliant?

“Both of them stepped up at short notice – very short notice – to absolutely call out the Government for their failure on the climate crisis and to hammer the Chancellor on his smoke and mirror Budget which does nothing for working people and nothing about the cost-of-living crisis.

“I’ll now be working from home but if you have symptoms or any cause for concern, please get tested to stop the spread of this virus.”

Former party leader Mr Miliband was greeted by ironic cheers from Tory MPs when he stood up in the Commons chamber.

It is the fifth time Sir Keir has had to self-isolate since the start of the pandemic – the most recent occasion was in July when one of his children tested positive.

Before the party announced the line-up change due to Sir Keir’s diagnosis, the Labour leader had tweeted: “The Budget must take the pressure off working people.

“With costs growing and inflation rising, Labour would cut VAT on domestic energy bills immediately for six months.

“Unlike the Tories, we wouldn’t hike taxes on working people and we’d ensure online giants pay their fair share.”