Green’s Dictionary of Slang

block n.6

[SE block, an impediment]

In phrases

put a/the block on (v.) (also put the blockers on, put the blocks to, put the box on)

to interfere with, to stop someone’s actions or plans, to defeat, to overcome.

[US]Ade ‘The New Fable of the Scoffer who Fell Hard’ in Ade’s Fables 255: The Memorable Day when he (Pallzey) had put the Blocks to Old Man McLaughlin, since deceased.
[Ire]B. Duffy Rocky Road 121: I often wish he was married to Mrs. Healey below, instead—she’d soon put the box on the hackles.
[UK]F.D. Sharpe Sharpe of the Flying Squad 246: Natural conditions bring about a state of congestion in which it is unnecessary for the pickpockets to ‘put the block on’ themselves.
[US]J. Thompson Savage Night (1991) 105: A punchy booze-stupe [...] could come along and put the blocks to you.
[UK]F. Norman Bang To Rights 124: They only thing they did was put the block on him.
[UK]F. Norman Guntz 19: He put the block on any of us having any more parties.
[UK]B. Naughton Alfie I ii: I told Gilda from the start that I ain’t the marrying sort and [...] she never tries to put the block on me.
[UK] ‘Metropolitan Police Sl.’ in P. Laurie Scotland Yard (1972) 321: block, the: an embargo on information, imposed from above.
[UK] in G. Tremlett Little Legs 121: The Old Bill were closing in, and they’d put the blockers on it.
[UK]Guardian 10 Mar. [Internet] Mr Murdoch has put a block on any further acquisitions apart from its pending bid for US satellite broadcaster DirecTV.
put the blocks on (v.) (also put the block(s) to)

1. to give someone a hard time.

[US]J. Thompson Criminal (1993) 83: I was putting the block to him.
[US]C. Stroud Close Pursuit (1988) 52: He puts the blocks to Mantecado about which you don’t want to know.

2. (UK prison) to tighten up regulations that have become temporarily lax.

[UK]P. Tempest Lag’s Lex. 19: blocks on, to put the. Tightening up of regulations against ‘fiddling’ or lax discipline.