Regents Park Barracks, Block K (The Officers Mess)

Regent's Park Barracks, Block K, known as The Officers Mess, is a building that served as officers' quarters and mess in a former cavalry barracks. It was constructed around 1820-1821, designed by the Barrack Department and built by Messrs. Baker & Nicholson. The structure originally had three bays added to the north and one to the south, with some existing windows altered between 1866 and 1867. It is built of yellow stock brick, featuring brick ridge stacks and a slated hipped roof, reflecting a late Georgian style.

The building has a single-storey and basement plan, with the left side housing single-depth mess rooms and the right side containing double-depth officers' rooms arranged around a central passage. The mess section has four tall windows and a central doorway with a flush-panelled door and overlight, while the quarters section features a main entrance two bays from the left, beneath a 20th-century canopy, leading to a doorway with a fanlight and panelled doors. The windows have gauged brick flat arches, and the southern half of the quarters section includes alternating blind windows.

Inside, the building retains its original mess dining room, ante rooms, and lower ante room, all of generous scale, with original plasterwork and an interesting cast-iron Adam-style fireplace. The dogleg stairs feature a column newel, plain rectangular balusters, and a mahogany rail.

Historically, this is the only surviving part of the original barracks, which was intended to accommodate about 450 officers and men and 400 horses. A barracks was initially laid out by John Nash as part of the Regents Park scheme in 1811, although the site was later moved to its current location backing onto the 1816 canal cut. This building is one of four new barracks associated with Nash's Metropolitan Improvements during a period of reduced barracks provision. While the rest of the barracks has been rebuilt, this structure follows the original plan. After the barracks at Deal, it is the oldest example of separate officers' quarters in England still in its original context and one of only five pre-Crimean War examples.