Cryptic crossword ACROSS

3. To impart some bias, assume a pretentious air (3,2,4)

8. Don’t include a circular letter to the Massachusetts Institute of Technology (4)

9. The shout of one getting engaged (6,3)

10. Mother isn’t upset by the insect (6)

11. Successfully handles the vestments (5)

14. He doesn’t win unusual roles (5)

15. See 21 Across

16. Checks restraints on figures (5)

18. Looks both ways (4)

20. Dance beat that’s accompanied with vigour (5)

21 & 15Ac. Exhibition stall dismantled – go off duty (5,4)

24. Almost blowing a bird out at sea (6)

25. Figured it’s a description of abandoned mine (6,3)

26. Skinhead before becoming old and withered (4)

27. Fly-trap, naturally (9)

DOWN

1. Stickler to give shape to a catalogue (9)

2. Wild females are strangely noiseless (9)

4. Arboreal feature of Pennsylvania in America (4)

5. Excel in an open-air celebration (5)

6. Given preference in the tournament, but surrendered, we hear (6)

7. Dreadful anger after the dispute starts (4)

9. Stand for ales, say (5)

11. Name the man who’s scratched, by the sound of it (5)

12. Change of one’s art not very much later (9)

13. Discovered in the nude, maybe – that’s baseless (9)

17. Away from home with a street porter (5)

19. Gambled on what a claim may be (6)

22. Drain relocated at the lowest point (5)

23. Stern deck where the petty-officer goes to work (4)

24. The colour of a trophy that is raised by the end of the game (4)