The TUC, the umbrella group for trade unions in the UK, is calling for Chancellor Rachel Reeves to consider a range of wealth taxes in November’s Budget to help boost investment in public services.

General secretary Paul Nowak told the BBC that people needed to see evidence of change.

“We need a progressive tax system – a tax on online gaming companies and gambling companies, a tax on windfall profits which the banks and financial institutions have seen over the last couple of years.”

In response, the Treasury pointed to previous remarks from Reeves, in which she said the government had “got the balance right” in taxing the better off, including new taxes on private jets and second homes.

In the interview, Mr Nowak called for Reeves “not to take anything off the table” and look at other options including equalising capital gains tax with income tax and, he said, “a wealth tax itself”.

“It has been introduced in other countries including Spain, which has one of the fastest growing economies.”

Individual unions are likely to make similar demands when the TUC’s annual Congress gets under way this weekend.

Mr Nowak focused in particular on the case for levying more from financial institutions.

“Banks have record profits driven by a high-interest environment.

“We think we can still have a profitable bank sector and ask them to pay their fair share.”

The prime minister reiterated this week that Labour’s financial rules were non-negotiable.

So, to meet the chancellor’s self-imposed constraints on debt and borrowing, tax rises appear to be inevitable in November.

The debate in the Labour movement – and elsewhere – is over who to tax and by how much.

Mr Nowak argued that “the big four high street banks made £46bn in profits in one year alone”.

Charlie Nunn, the chief executive of Lloyds Bank, has previously spoken out against any potential tax rises for banks in the government’s Budget announcement this autumn.

He said efforts to boost the UK economy and foster a strong financial services sector “wouldn’t be consistent with tax rises”.

And when the left-leaning think tank the IPPR suggested further taxing bank profits, share prices fell.

Asked if this approach could make the markets jittery and potentially drive investors away, Mr Nowak said: “Britain is an attractive place for international investors” and he suggested there hadn’t been “an exodus of millionaires” after tax changes for non-doms and ending the VAT exemption for school fees.

He claimed that the TUC’s own polling suggested that introducing wealth taxes to fund public services was most popular among voters who had gone from Labour to Reform UK.

Nigel Farage’s party conference begins on Friday in Birmingham and Mr Nowak issued this warning to Keir Starmer: “Change still feels like a slogan not lived reality. There is a real danger if the government doesn’t deliver the change people want, they will become disillusioned with mainstream politics, and some will look for divisive alternatives like Reform.”

While the chancellor has been far from keen on a conventional wealth tax on assets, some in the wider Labour movement are pressing her to look at how those with “the broadest shoulders” pay more.

There is some hope that with a new economic adviser now ensconced in Downing Street and reporting to the prime minister, that the debate on tax is more open than before.

That adviser – Baroness Shafik – has called for taxation on wealth and land in the past.

“The public aren’t daft – they know there are difficult choices,” said Mr Nowak.

“We need a grown up conversation.”

A Treasury spokesman told the BBC that the government’s number one priority was to grow the economy and pointed to the chancellor’s words last month.

Rachel Reeves said: “We introduced increased taxes on private jets, on second homes and increased capital gains tax.

“So I think we’ve got the balance right in terms of how we tax those with the broadest shoulders. But any further decisions will be ones that are made at a budget in the normal way.”