I never met Mick, but for as long as I remember, he has been part of the Natural History Museum's Entomology Department's legendarium. Perhaps he is best know in the department as one of the intrepid 5 scientists who drove a mobile laboratory all over southern Africa in the 1970s! There is a blog below about this slightly madcap but extremely scientifically successful expedition, and I have also uploaded a photo of the five of them: 

from left to right:
Brian Cogan, David Hollis, Peter Hammond, Michael C. Day (Mick), Richard Vane-Wright (Dick)

https://naturalhistorymuseum.blog/2016/11/24/the-museum-homemade-mobile-field-laboratory-explore-your-archive-week-library-and-archives/

The thousands of specimens they collected included many new, previously undiscovered species and are now in the Natural History Museum alongside the entomological fruits of Darwin's Beagle Voyage, Captain Cook's Endeavour trip, and other great expeditions of exploration and discovery. Around 20 new species of insects, across various groups in NHM, bear the scientific name 'dayi' in honour of Mick Day

Max Barclay (Senior Curator of Beetles, Natural History Museum)