Just to pick up on a few points made in this thread - Freakbeat certainly wasn't a response to US psychedelia. Freakbeat was a term invented and used retrospecvtively from the early 80s to describe post-beat mod/pop-art/proto-psych, invented by Phil Smee of Bam Caruso along with the originators of Freakbeat fanzine, though their definition was different.
US garage had very little influence in the UK at the time. Bands like Music Machine, Count 5, ? and The Mysterions, Blues Magoos, Seeds and Prunes all had records released in the UK at the time and none charted, though perhaps 'Too Much To Dream' got to number 40 or something. The UK was always heavily influenced by US sounds but the BIG influences on the UK through '65 and '66 were The Byrds, Dylan and The Beach Boys. Even the 'polished garage' of Paul Revere made no impact at all over here.
Psychedelia was certainly a US invention, though similar revolutionary drug-fuelled counter-cultures were developing simultaneously in the major European metropolitan centres, notably Amsterdam and London. US psych had very little influence on the sound of UK psychedelia, partly because US psych was read about long before it was ever heard in Britain. So UK psych sounded very different, being quite freeform and avant-garde live, while being very 'pop' generally on record. The UK scene was dominated by a handfuul of major labels which meant most 45s were made to sound both polished and commercial throughout the 60s. You just didn't get the same rawness or primitivism on UK records.