The number of Post Offices open across Britain has dropped by more than a third as campaigners warn that access to cash is getting harder.

Every region in England and Wales has seen a decline in the number of Post Offices in the last 20 years, with 6,700 disappearing in that period.

Post Offices now commonly provide banking services to rural communities, and have become a lifeline in many towns and cities in recent years.

More than 6,100 banks and building societies have closed their doors since January 2015, according to consumer group Which?. In the majority of cases, customers have been signposted to local Post Offices instead.

At the beginning of the millennium, there were 18,393 Post Offices. By 2023, this had dropped to 11,684, according to Telegraph analysis.

The biggest fall was at the height of the financial crisis, between 2008 and 2009, when the number dropped by 1,615.

Wales has the most branches, with 30 per 100,000 people. But it is also the area which has experienced the biggest decline in service in recent decades, as there were 43 Post Offices per 100,000 people in 2004.

The region which saw the second largest drop was the South West, which previously had 33.2 Post Offices per 100,000 people, but had just 21.6 by 2023.

The worst served region was London, with just eight Post Offices per 100,000 in population, down from 13.6 in 2004.

Government rules mean that 99pc of the population must live within an hour’s walk of a Post Office, or three miles, and nine in 10 must be within just one mile of their nearest outlet.

In deprived urban areas, 99pc of the population must live within one mile, whereas 95pc of those in rural areas must be within three miles. The population of urban centres typically lives closer than those in more remote rural areas.

Post Offices now commonly provide cash services to rural communities, and have become a lifeline for places which have lost their bank branch.

They handled a record £3.7bn in cash in July this year, as cash usage remains steadier than expected. More than 6,000 bank branches have shut since 2015, with many of the biggest banks blaming a drop in the number of customers using them.

But campaigners warned that the current demand for cash would put too much pressure on the remaining Post Offices.

Martin Quinn, of the Campaign for Cash, said: “Rural areas again are being left behind with access to cash services. Wales has been especially hardest hit and the Post Office network cannot cope. The banks have abandoned rural communities, banking hubs although a help, are a drop in the ocean.”

A spokesman for the Post Office said: “The size of the Post Office network has remained stable over the past decade. We have more than 11,500 branches across the UK in line with our Government requirement.

“The Government also sets us five access criteria and we also met all of these requirements. We continuously monitor the network at a very detailed, local level to ensure that it remains sustainable for customers to access the Post Office products and services they require.”