Caci said growing numbers of people owning a smartphone was partly behind the increase.
It said mobile banking’s growth is being fuelled by the increasing adoption of the technology by older generations, in particular wealthier older families and those nearing retirement.
The proportion of customers using app banking is expected to continue to rise over the coming years, reaching 71 per cent by 2024.
Meanwhile the proportion of branch users will steadily decline to 55 per cent by that year, according to the predictions.
The tipping point at which mobile banking is expected to draw level with branches in terms of the proportion of customers using it and then overtake this method is predicted to happen in 2021, when 59 per cent of customers are expected to use mobile banking and 59 per cent are predicted to use their branch.
Caci said that, rather than mobile banking app users giving up using bank branches, the technology is supplementing branch use.
The firm said that the decline of branch visitors is modest – and even in five years’ time more than half of customers will still be visiting branches.
The Growth of Digital Banking 2019 report also said that peer-to-peer lending is attracting new audiences to the savings market.
Jamie Morawiec, an associate partner at Caci and the author of the report, said: “While digital – and mobile in particular – is clearly a frontrunner for the future of banking, there is a huge potential for financial institutions to tap into unexplored markets such as younger customers who have current accounts but aren’t necessarily saving yet.
“The increase in popularity of peer-to-peer lending, alongside the rise of the challenger banks, will change the landscape for traditional banks.
“To stay tapped into the savings cross-sell, banks must offer a seamless, tech-driven user experience.”
Trade association UK Finance’s annual Payment Markets report said more than two-thirds of UK adults (71 per cent) used online banking and 41 per cent used mobile banking in 2018.
A spokesman said: “More and more customers are now opting for the speed and convenience of using mobile banking to check their balances and make transfers while on the move.
“This rapid rate of technological change is set to continue over the coming decade.”