Britain’s biggest banks face a windfall tax on their ‘stellar’ profits as new Chancellor John Healey looks for easy targets to balance the nation’s books, according to some of the sector’s most senior analysts.

The scale of the bonanza will be laid bare this week when Lloyds, NatWest and Barclays unveil their latest results.

These are expected to show that they are on track to make almost £19billion between them this year, up from just under £16billion in 2025, according to City forecasts.

Banks have gained from higher-for-longer interest rates, which have boosted their net interest margin – a key financial gauge that measures the gap between what they pay savers and charge borrowers.

The bumper profits have already led to calls from across the political spectrum for an extra levy to be imposed, with some industry watchers predicting a windfall tax is almost guaranteed.