Yorkshire has the lowest ratio of bank branches to people of anywhere in the UK after a wave of closures that has left many places without a single outlet, research has found.

The Yorkshire and the Humber region now has 248 branches left to serve a population of 5.6 million people, according to consumer group Which? That equates to 4.4 branches for each 100,000 people, “leaving every Yorkshire resident sharing their branch with 22,557 others”.

The number of UK bank branches that have shut their doors for good over the last nine years recently passed 6,000: Which? said the latest number was 6,161 branches shuttered since 2015. Across the country there are now thought to be 30 parliamentary constituencies – totalling just above 3 million people – without a single bank branch.

Fresh rounds of closures are seemingly being announced every few weeks. Earlier this month it emerged that Lloyds Banking Group plans to close a further 55 branches across its Halifax, Lloyds and Bank of Scotland brands.

Typically, banks justify the reduction on the grounds that customers are spurning traditional counter services in favour of banking online and via mobile phones.

At the start of 2015, Yorkshire and the Humber had 728 open branches, equivalent to 13 for each 100,000 people. Since then, two-thirds of the number of outlets – 480 – have closed.

The region now has nine parliamentary constituencies without a bank branch, all of them represented by Labour MPs, including Barnsley South, Bradford South, Doncaster East, and the Isle of Axholme, Sheffield Hallam and York Outer.

According to Which?, Barclays has axed the most branches (92) in the region since January 2015, followed by HSBC (73) and NatWest (69). The Halifax – the building society turned bank that was established in Halifax, West Yorkshire, in 1852 – has kept the largest presence of any bank brand in the area, with 43 operational branches.

While Scotland had the “best” access to branches, at 6.9 outlets for each 100,000 people, its population is spread unevenly across the country, and those living in more rural areas still face long journeys to use a bank.

The decline of the bank branch network has left many communities without vital services – in particular the ability for some shopkeepers and small business owners to deposit takings without having to close early or travel for miles.

Some banks insist on customers coming to a physical branch to carry out certain tasks, such as registering power of attorney.

However, new regulations that came into force this month mean banks and building societies have to ensure that any communities they are leaving have other ways to access cash.

The aim is that “banking hubs” – with a counter service where customers of almost any bank can withdraw and deposit cash, make bill payments and carry out regular transactions – will play a vital role in replacing shuttered branches. However, the consumer body said that their rollout “remains far too slow for consumers to feel their benefits”.

Sam Richardson, the deputy editor of Which? Money, said: “While Yorkshire and the Humber may hold the dubious record for the worst branch access, this is a nationwide problem.”