Green’s Dictionary of Slang

thank you.

1772		Mrs Delany in Vulliamy Life and Letters (1935) 457: My dearest child [...] You would not say ‘Ta’ to me for my congratulations.
1879		Clarence & Richmond Examiner (Grafton, NSW) 18 Jan. 4/6: Ta awfully ta.
1879		Mons. Merlin 21 Mar. 7/2: A young lady accepting a bouquet from an admirer graciously acknowledges the gift with the words, ‘Oh, thank you so much. Ta! awfully ta!’.
1943		R. Llewellyn None But the Lonely Heart 184: ‘Ta, Ma,’ Reg says.
1959		W. Hall Long and the Short and the Tall Act I: mitchem: Fag? johnstone: (taking the cigarette) Ta.
1978		A. Ayckbourn Joking Apart II ii: Yes, ta. Leave it there for me.
1981		T. Wilkinson Down and Out 52: ‘Yeah, ta,’ she replied.
1999		Indep. 6 Sept. 20: ‘Have you got a light? [...] Ta,’ said the man.