Concemore Thomas Thwaites Cramp (19 March 1876 – 13 July 1933), known as Charlie Cramp, was a British trade unionist and political activist.

Born in Staplehurst in Kent, Cramp worked as a gardener, before gaining employment with the Midland Railway. He worked as a porter based in Shipley and then Rotherham, where he was promoted to become a guard, and joined the Amalgamated Society of Railway Servants (ASRS). Soon after, he moved to Sheffield, where he married an Elizabeth Baker, also from Staplehurst.^[1]

Cramp was an effective trade unionist, and was elected to the executive of the ASRS in 1911, immediately prior to a major strike.^[1] The ASRS merged with other unions in 1913 to form the National Union of Railwaymen (NUR).^[1] Cramp maintained his position on its executive, working during World War I to oppose further strikes, and was elected as President of the NUR in 1917.^[1][2] He was also appointed as Industrial General Secretary of the union, a full-time position in which he was seen as deputy to General Secretary James Henry Thomas.^[1]

Cramp was also active in the Labour Party. He stood unsuccessfully for it in Middlesbrough West at the 1918 general election.^[3] He was a member of its National Executive Committee from 1919 until 1929, and served as Chair of the Labour Party in 1924/5.^[1][2] The following year, he was elected as President of the International Transport Workers' Federation.^[4] In 1929, he was elected to the General Council of the Trades Union Congress, serving for three years,^[2] thereby swapping positions with Thomas. In 1931, Thomas was given a ministerial position, and Cramp took over as General Secretary, but he died suddenly two years later, aged 57.^[1]