UK Argo was part of the UK Decca empire. It was founded by a wonderful chap named Harley Usill who set it up mainly to cover spoken word recordings, train recordings (!) and some folk music. Jazz came into the fold thanks to the link with Michael Garrick, who did much of his best work for the label, in a very sympathetic environment. The whole thing folded in the late 70s when Polygram (I think) bought them out and I understand that the clear out of subsidiaries such as Argo was done ruthlessly and poor Harley was treated very badly. A sorry affair.
The last Garrick Argo LP, ‘Troppo’, is one of his very best but sold in low numbers.