Is this Hydrotaea diabolus please? Beds. 7 September 2021. Support for that ID comes from Steve Crellin via Facebook. Reason why it might not be diabolus is because the haltere is rather dark and it should be yellower for that species. Trouble is it doesn't key to any of the species with a darker haltere (some are rare anyway, whereas diabolus is supposed to be common).
