The home secretary was grilled by Good Morning Britain presenter Susanna Reid in the wake of chancellor Rachel Reeves hiking taxes by £40 billion in last week's Budget.

On GMB this morning, Reid told her: "This is what we were told by Labour spokespeople before the election. Have a listen."

Cooper was then shown a succession of senior Labour figures who all said that further tax rises would not be needed after the election.

Darren Jones, now chief secretary to the Treasury, said: "All of our manifesto is fully funded and fully costed. There is no need to make further changes to other taxes."

Jonathan Ashworth, who lost his seat at the election, said: "Our tax plans are clear and our manifesto does not need further tax increases."

And Pat McFadden, who is now chancellor of the Duchy of Lancaster, told the programme: "There is nothing in the manifesto, nothing in the plans that we published today, that will require further tax increases."

Reid then asked Cooper: "Were we lied to?"

The home secretary replied: "Clearly when we arrived in government, we did discover that there were substantial commitments that had been made that were unfunded."

But Reid said: "The black hole is £22 billion. The tax rises - £40bn. The number doesn't add up."

Cooper said: "It's right that the difficult decisions that Rachel Reeves has taken have been about how you fix the gap in the public finances that we inherited, how you also make sure that you get the growth that we need and also deal with the parlous state of the National Health Service."