Cryptic crossword - The Scotsman 18/04/13

Across

1 I’m having to take one mask off; you can be sure of it (4,2,7)

10 It can be a real boost to get into nice places (5)

11 To open every class is a major undertaking (4,5)

12 Calculating how to be both popular and plain-speaking (9)

13 Is remiss to go slow in recession (5)

14 Did old man barge over the barrier? (7)

16 Put one’s foot down to block old and new (5,2)

18 Avant-garde artist took a little girl on dock visit (7)

20 Live with you, we’re told, on balance (7)

21 Alas, the audience heard it incorrectly (5)

23 For small number, moreover, that’s as far as it goes (2,7)

25 Followers escort bodyguard onto a train (9)

26 Would a learner, very often, display some backbone? (5)

27 Subordinate succeeded, to some extent, but failed to reach potential (13)

DOWN

2 Some workers have to take turn with relatives (5)

3 Unconventional character as mad as a hatter (9)

4 Although very active, and working on time, he had to leave (2,3,2)

5 Maybe one will have to point to disability (7)

6 Furthermore, left small gadgets in appliances (5)

7 Novel way to have made off with baby as she slept (9)

8 Did he impress the rest, with little hesitation, but refuse to take action? (6-7)

9 Had he taken over border when depressed? (6-7)

15 Head boy, at short notice, took some fine pottery into court (9)

17 Profession of word of honour, in confidence (9)

19 Left three articles, over time, to produce showy shrub (7)

20 Is about to be presumptuous, in order to fix things up (7)

22 Turn into second one with some relish (5)

24 Manage to shore up gymnastic apparatus (5)