This pub is not a listed building, but it is on the Campaign for Real Ale’s (CAMRA) Local Inventory as having an interior of Local Historic Interest, and the description is as follows: "This pub of considerable charm and character appears on first sight to be of great antiquity, but closer inspection reveals that it has been subject to considerable alteration over the years. There was certainly a pub in the building in the 19th century, with the essentials of the current layout visible on plans dating from 1906, but the configuration of the interior was modified during or before 1947 and again in 1974.

On entering the main door, there is a small ground floor with two fireplaces. Wooden panelling on the walls is covered with old artefacts and memorabilia, although the majority were probably purchased and installed in the late 20th century, including the stoves which have been placed in the fireplaces. Old photographs suggest that the bar counter may be made from the timbers of an older bar, and the unusual beer engines date from the mid-19th century. The back of bar was probably constructed in 1974; there is an illuminated brewery logo on the fascia. The current bar was knocked together from a tiny public bar and smoke room, and the counter has at least been moved from the position it occupied between 1906 and 1947. Stairs lead to a small upstairs drinking area.

A second set of stairs lead downwards to a lounge. This is again wood panelled with a fireplace at the rear of the room,. The floor consists of stone flags which may predate the mid-20th century modifications. Plans reveal that in the early 20th century the bulk of this area was occupied by a kitchen, but a larger space was created, probably during or before 1947 by the removal of the kitchen. The downstairs bar counter was installed at the same time.

Although partitions have been removed, the basic early 20th century configuration in the ground floor and lower bars can still be detected. Despite the uncertainties surrounding the age of many of the fittings and the dates of the mid-century internal modifications, the pub is undoubtedly of Some Regional Interest."

The WhatPub link is here: WhatPub/Nags Head

The Nags Head featured on the Evening Crawl of Belgravia in September 2002, the Cavaliers and Grenadiers; Evening Crawl of Knightsbridge and Belgravia in August 2009, and the Mews and Booze: Evening Crawl of Belgravia and Knightsbridge in September 2012.