A slang term for a catspaw, a fawning and obedient follower, a lackey. Apparently British twentieth-century slang, having originated in a speech by Lloyd George against the Prime Minister's use of the House of Lords, supposedly an independent guardian of liberties, to rubberstamp his decisions:
The House of Lords consented. This is the defender of property! This is the leal and trusty mastiff which is to watch over our interests... A mastiff? It is the right hon. Gentleman's poodle. It fetches and carries for him. It barks for him. It bites anybody that he sets it on to.
Hansard, 26 June 1907
The word 'poodle' came into common currency in this sense. The House of Lords was referred to as 'that Tory poodle' (1944); Roy Jenkins wrote Mr Balfour's poodle (1954), an account of the struggle involving Lloyd George; and we have since then had people called, or denied being, anybody's poodle, the poodle of the BBC, and so on. In recent years it has been kept in the public mind by its graphic depiction in the works of the trenchant satirical cartoonist Steve Bell in The Guardian.
Another colloquialism is poodle-faker for a ladies' man, a man who insinuates himself into the company of women. This may be military or naval in origin, as it also means a newly commissioned officer. Then there are terms such as poodledom for the state in which a man stays at home under the thumb of his wife, doing little.