The present church, which combines a plain, unadorned Gothic Revival exterior with a lavishly decorated interior featuring extensive early 20th-century paintings by Nathaniel Westlake, is the third building used for Roman Catholic worship in the seaside resort.

James Burton's new town of 1827, immediately west of Hastings, was home to a convent from 1848; public worship then transferred to a new church nearby in 1866.

The church remains in use as the main place of worship in a parish which extends into nearby Hollington, and has been listed at Grade II by English Heritage for its architectural and historical importance.

In 1828, he bought a large area of wooded, sloping land (formerly part of the Manor of Gensing) which had a long shoreline facing the English Channel.

He spent the next few years laying out a high-class planned community with houses, shops, hotels, markets, an Anglican church and facilities suitable for a fashionable seaside resort.

John Jones, the Honorary Chaplain of the Bavarian Embassy in London, received from the will of Lady Barbara Stanley a bequest of £10,000, 16 acres (6.5 ha) of land and a house in St Leonards-on-Sea, all to be used for "religious purposes" for the benefit of Roman Catholics.

They declared it unsuitable, and the proposed chapel and convent—large, intricately designed buildings in the Italianate style, conceived by Charles Parker—were not built.

Builder Edmund Boniface executed Buckler's design, and the new Church of St Thomas of Canterbury and English Martyrs opened to the public on 6 July 1889.

[10] There is a great contrast between the austere, minimalist exterior of the Church of St Thomas of Canterbury and English Martyrs and its elaborately decorated interior.

[9] His church at St Leonards-on-Sea was a good example of this: typical Gothic exterior features included trefoil and tall lancet windows, a multi-sided apse and buttressing.

The vividly coloured painted murals, some purely decorative and some representative of Biblical scenes, date from 1908–1911 and have been repaired and enhanced since.

[9][12] Nathaniel Westlake's images include St Michael (in the side chapel dedicated to St George), the English Martyrs and the Hand of God above the chancel arch, various saints and prophets on the chancel ceiling, a Nativity on the south wall and a Last Supper on the north wall.