Britain’s leading consumer group has called on banks to justify nearly 13,000 bank branch closures that have left millions of people struggling to access vital financial services across the UK.

Figures compiled by the consumer charity Which? show that the UK has lost nearly two-thirds of its bank and building society branches over the past 30 years, from 20,583 in 1988 to 7,586 today.

The loss of those sites has left 19% of the population more than nearly two miles away from their nearest branch, while 8% now have to travel more than three miles, with Scottish communities hardest hit by closures.

Thinly-populated areas of Scotland account for 70 of the communities farthest from a branch, though Which? said the south-west and east of England had been “disproportionately affected” given the size of regional populations.

Among the towns and villages now lacking a single bank branch are Lymm in Cheshire, Sturminster Newton in Dorset, Fishguard in Pembrokeshire and Broseley in Shropshire.

Ceri Stanaway, money editor for Which?, said: “The true scale of bank branch closures in recent decades is staggering and has left millions of people struggling to access the vital financial services and cash that they need.

“For many there is simply no substitute for a dedicated branch and the wide range of services it offers, and many customers now face having to travel long distances if they are to avoid financial exclusion.”

Banks including RBS, Barclays, HSBC and Lloyds have significantly reduced their bank branch footprint in recent years in an effort to cut costs amid a digital banking push. Those lenders have turned to the Post Office to offset closures, with postmasters across 11,547 sites offering basic transaction services in their stead.

But Which? said customers are hesitant to use the Post Office’s banking services, citing long queues, a lack of privacy to deal with financial affairs and concerns about a lack of financial expertise. Its survey showed that 60% preferred to deal directly with their bank.

Post Office sites are also restricted in the services they can offer, with customers unable to open or close accounts, transfer money between accounts, request a debit card replacement or make a complaint about their bank.

The UK has lost nearly two-thirds of its bank and building society branches over the past 30 years. Photograph: Alamy

Stanaway said: “We want to see banks properly justifying the reasons for closure and taking into account their customers’ needs before shutting their doors – and their customers out.”

The Post Office said in a statement that it took its responsibility “very seriously” and was “uniquely placed to bring vital services to local communities right across the country”.

But Mike Cherry, national chairman of the Federation of Small Businesses, said the Post Office should be “doing more, to both improve its small business banking offer and make more firms aware of it”.

He added that bank branches were still “vital” to small business owners in areas where internet services were still lagging, or whose customers preferred to pay cash.

“Bank branch closures damage high street footfall, restrict cashflow in local economies and force business owners to waste time travelling to and from their next nearest branch, which could be miles away.

“Yes, small business owners need to consider alternative ways to bank, but the sheer pace of branch closures is frightening. Firms need time to adjust.”