Scottish Labour leader Michael Marra has called on the Chancellor to increase taxes on big banks.
John Healey is due to lay out his first Budget on Wednesday.
Mr Marra – himself new to the party leadership in Scotland – has pushed for big firms to “do their bit”, echoing calls from the TUC last week.
Profits have spiked for big banks, with a 12% increase for Barclays in the third quarter of this year, driven, Mr Marra claimed, by “mortgage rates way outstripping the base rate and savings rates not doing so”.
The Scottish Labour leader will meet the Chancellor and Energy Secretary Miatta Fahnbulleh this week.
“Labour governments should make progressive choices on tax,” Mr Marra said.
“Labour has already asked the wealthiest and richest to pay more: taxing private jets, private schools and private equity to raise revenue for public services like our NHS.
“Our financial services sector is strong and internationally competitive, so much so that in the first six months of this year the biggest banks have made around £15 billion of profits.
“That didn’t come in efficiency savings, but mortgage rates way outstripping the base rate and savings rates not doing so.
“When people are struggling to afford to turn up the heating, we should ask big business to do their bit – especially when they are seeing windfall profits.
“The banks paying their fair share would be a good place to start to fund measures that give people a bit of breathing space.”
It is understood Mr Marra remains open to how tax can be increased on big banks, with a hike from the current 3% they pay in corporation tax surcharges a potential avenue.
But a Treasury spokesman refused to engage with the suggestion ahead of Mr Healey’s autumn statement on Wednesday.
“As has always been the case, decisions on tax are a matter for the Chancellor to set out at fiscal events, rather than routinely commenting on rumour, speculation or proposals,” the spokesman said.