This species has only recently been recognised in Britain, previously being confused under the name T. unicolor. Most records of the latter belong to the present species.
Both Tachysphex unicolor and T. nitidus are present in the British Isles. The separation of the two species has not been adequately documented in the English language, but is correct in Bitsch et al., 2001 Faune de France 86. Unless explicitly stated that this key has been used, or any subsequent one which recognises this situation, all records should be placed in agg.
North Devon to Kent (including the Dorset coast, but apparently not the Isle of Wight); the south Wales coast, and north to North Lincolnshire, Westmorland and the Isle of Man. In the Channel Islands, the species appears to be confined to Guernsey. Overseas it is found in northern and central Europe southwards to southern Spain, the Canary Islands and North Africa. The range extends eastwards to Syria and Israel.
The first map is records of T. nitidus agg and includes both T. unicolor and T. nitidus. The second map is for Tachysphex nitidus iso Bitsch et al., 2001