Luckily it's one of the more distinctive ichneumonids: Hepiopelmus variegatorius. I's a species of the subfamily Ichneumoninae, which are all parasitoids of Lepidoptera, either larvae or pupae, but always emerging from the pupa. Hepiopelmus variegatorius attacks Ermine (Spilosoma species) larvae. It's probably not very common but it does tend to get noticed, so I receive a fair few photos for identification. There are large numbers of attractively marked species of Ichneumoninae, usually basically black with copious yellow, red or white marks. Sometimes it is possible to identify the species confidently from photos, although with some species it's not possible.