The 23 class were rigid airships produced in the United Kingdom during the First World War. They were designed by Vickers, who also built the first and last of the four ships, with the other two being built by William Beardmore and Company and Armstrong-Whitworth. While the 23 class was never used in combat, the four ships provided many hours of valuable training and experimental data for British airship crews and designers. Although a total of 17 of these ships were contemplated at one time, only four were ever built. The 23 class was found to be significantly overweight, leading to its cancellation in favour of the more-refined R23X class.