7 City built from 1960, whose architect was Oscar Niemeyer (8)
8 1960s slang for a hippie community (6)
10 Molecule whose double-helix structure was discovered in 1953 (3)
11 Twentieth century painter of Constables, Rembrandts, etc. who died in 1984 (3,7)
13 1960s slang term for an animal kept by criminals and trained to attack (4,3)
15 Information service established by the BBC in 1973 adding pages of text to the TV display (6)
16 The type of currency adopted in the UK on the 15th of February 1971 (7)
17 Estate agent in the city of Zenith in a 1922 Sinclair Lewis novel of the same name (7)
20 Collie-dog film star (6)
22 UK centre of film making near Borehamwood (7)
23 Prefatory phrase of a joke which is answered by ´Who's there?` (5,5)
26 The ---, nickname of the actor Warren Beatty (3)
28 Jewel thief; hired assassin (6)
29 Social activity after winter sports (5-3)

1 1970s slang for an aggressive lesbian (8)
2 UK pressure group against smoking (3)
3 Advertising equivalent of an Oscar (4)
4 ---holiday, holiday whose price is all-inclusive (7)
5 --- strip, territory created in 1948 when Egypt occupied it following UN proposals for the division of Palestine (4)
6 According to the theory of Plate Tectonics a single supercontinent which broke up to form the present continents (alt. spelling) (6)
9 Werner ---, German physicist and author of the Indeterminancy Principle published in 1927 (10)
12 Marketing term meaning to pool ideas rapidly before assessing their value (10)
14 --- Brass Plate, a brass plate found near San Francisco in 1936 which named the area New Albion and was dated 1579 (5)
15 --- theory, a mathematical theory of the unpredictable behaviour of systems (5)
18 1960s pop group with a quirky English style (3,5)
19 Large pellet-filled cushion popular as a furniture item in the 60s and 70s (7)
21 Anti-aircraft guns (3-3)
24 Citizen ---, 1941 film by Orson Welles (4)
25 The ---, 1911 novel by Arnold Bennett (4)
27 Dangerous drug giving rise to psychedelic experiences (3)