As part of the celebrations, the staff are dressing up in period costumes, displaying historical banking documents and equipment and sharing a giant birthday cake with their customers.
NatWest's Tonbridge branch first opened in 1836 as one of the newly formed Surrey, Kent and Sussex Banking Co's first branches.
Tonbridge had been continuously expanding since a Navigation Act in 1740 granted the Medway Navigation Company permission to manage the use of the river Medway as far as the town, allowing goods such as coal and lime to be transported to Tonbridge, and other locally produced goods, including hops and timber, to be carried to nearby Maidstone and to London. The steady growth of Tonbridge attracted the attention of the bank's directors and the Tonbridge branch was opened, under the management of Mr Charles Parker.
The original location for Tonbridge branch is unknown; however it is believed to have been in the High Street. The arrival of the railway in Tonbridge in 1842 caused the population of the town to expand rapidly as it made it possible for people to live in Tonbridge and work in London. In 1866 it was agreed that larger premises were required for the branch, and so a new building was purchased at 139 High Street.
Various bank mergers saw the branch change its brand over the years and by 1923 when it was trading as Westminster Bank it had again outgrown its premises. A suitable site was found at 130 High Street, from which the branch began trading on 5 November 1923 and still remains today. In 1968 Westminster Bank and National Provincial Bank announced their intention to merge. The operations of the banks were combined over the following 18 months and all branches including the one in Tonbridge began to trade as National Westminster Bank from 1 January 1970.
Commenting on the celebrations, Christine Thompsett, Branch Manager at NatWest's Tonbridge Branch, said: "My team and I are delighted to be celebrating the fact that NatWest has been operating a banking service for the people of Tonbridge for 175 years. We are proud of our close association with the town and look forward to celebrating this occasion with our customers, as well as continuing to provide a high quality service to the local community."