Green’s Dictionary of Slang

bubble (and squeak) v.

to speak, esp. to inform to the police.

1935		A.J. Pollock Und. Speaks 14/1: Bubble and squeak, speak.
1944		Maurer & Baker ‘“Aus.” Rhyming Argot’ in AS XIX:3.
1960		J. Franklyn Dict. of Rhy. Sl.
1970		‘Metropolitan Police Sl.’ in P. Laurie Scotland Yard (1972) 321: bubble, to: to put in for X: to disclose damaging evidence about X.
1977		D. Powis Signs of Crime 175: Bubble (and squeak) To inform (speak) against: ‘Put the bubble in’ or ‘Bubble him’.
1989		S. Armitage ‘The Stuff’ in Zoom 69: Someone bubbled us. CID sussed us / And found some on us.
2000		J.J. Connolly Layer Cake 13: It’s a known fact that they’ll bubble you up when they’re chucking. [Ibid.] 29: They, the fuckwits, are either grafting against all odds, bubbling one another up, or bleeding starving.
2023		Twitter 11 Aug. 🌐 ‘[Nadine Dorries] thought she could get £85k a year for milling about and topping up with her Friday Night show on the Fash Channel...Now some pests have bubbled her!’.

In phrases

put the bubble in (v.)

(UK Und.) to inform.

1977		D. Powis Signs of Crime 175: Bubble (and squeak) To inform (speak) against: ‘Put the bubble in’ or ‘Bubble him’.
1982		P. Redmond Tucker and Co 14: We all have to watch it in case he jumps us. Someone should put the bubble in.
2000		J.J. Connolly Layer Cake 215: Jimmy would be putting the bubble in and expecting a squeeze from the Other People in return.