"This Was" received generally favourable reviews and sold well upon its release. "Record Mirror" thoroughly recommended the album in 1968 for being "full of excitement and emotion" and described the band as a blues ensemble "influenced by jazz music" capable of setting "the audience on fire". Allen Evans of "New Musical Express" wrote in his review that the album "sounds good and has a lot of humour about it" and that the band "play jazz really, in a soft, appealing way, and have a bit of fun on the side with tone patterns and singing". American critic Robert Christgau, on the contrary, was appalled by the success of a band that combined "the worst of Roland Kirk, Arthur Brown, and your nearest G.O. blues band."