Last week, Mr Burnham used his first interview since returning to Westminster to say that, while he intended to stick to Labour’s manifesto commitments not to raise VAT, income tax or national insurance, he believed there was still “some room” for movement.
His top ally Louise Haigh has led calls for a sharp increase in CGT, while Wes Streeting, the former health secretary, has said it should be brought in line with income tax.
Both are expected to be handed senior roles in Mr Burnham’s Cabinet.
Last week, The Telegraph revealed that Ms Haigh, who is playing a key role in devising his domestic policy agenda, said CGT should be “brought closer” to income tax.
CGT is levied on the profits made from selling an asset that has increased in value, such as shares of a property that is not a main home. Equalising CGT with income tax would almost double the rate, from 24pc to as much as 45pc.
Mr Ward-Jackson said this would be the highest rate in Europe. “While everyone else is racing to attract entrepreneurial talent, we would be punishing them and making ourselves poorer as a result,” he said.