Small colourful wasp?

Small colourful wasp?

Observation - Small colourful wasp? - UK and Ireland. Description: It was flying between little holes in the concrete of the landward side of the seawall, there were at least two of them and one was noticeably larger than the other but other than that it was identical.

It was flying between little holes in the concrete of the landward side of the seawall, there were at least two of them and one was noticeably larger than the other but other than that it was identical.