Green’s Dictionary of Slang

dead and buried.

1859		C.J. Lever Davenport Dunn 215: ‘He is dead, poor fellow,’ said Conway, gravely. ‘I expected to have met you at his funeral.’ ‘So I should have been [...] but as in seeing old Paul “tucked in” they might have nabbed me.’.
1916		C.J. Dennis ‘Introduction’ in Moods of Ginger Mick x: Whenever some sich bloke as ’im wus tucked away fer good / I’d chalk them words above ’is ’ead: ‘’E never understood.’.
1934		E. Pound letter Apr. in Paige (1971) 256: Why the hell don’t you have a bit of real fun before you get tucked under?