Total customer accounts at Starling rose to 4.2m from 3.6m and card spending went from £16.5bn to £19.9bn. Fixed term deposits flew from a standing start to £430.6m, helping total deposits increase by 4.0% to £11.0bn. John Mountain, interim CEO, says: "Although higher base rates undoubtedly provided a strong tailwind, boosting our net interest margin to 4.34% from 2.72%, we grew by attracting more customers in a competitive market because we deliver great experiences, both through our app and our UK-based customer service agents." The bank is expecting to grow profits further through the launch of its Banking-as-a-Service proposition Engine, which has already signed its first two clients in Australia and Romania.

Starling investor Chrysalis last month forecast that Engine could generate hundreds of millions of pounds a year for the UK digital bank, propelling it towards a £10 billion valuation. Mountain says: "Looking to the future, I see in Starling a well-capitalised bank that has grown rapidly but that has captured 2.8% of the UK current account market so far, leaving significant headroom for further domestic expansion. In Engine, I see a world-class technology provider that has just begun to crack open a £91bn global addressable market for SaaS."

He says that Starling remains committed to a public float in London. While a date had not been set, discussions in board meetings and with shareholders had focused on plans for an IPO.

Mountain will step aside in the next few weeks to make way for Raman Bhatia, the chief executive of energy retailer OVO and former HSBC digital banking lead, who will take over the reins following the departure of founder Anne Boden and will lead the firm’s IPO planning.