1		In medicine, the presence of one or more obstructing clots, etc in the blood vessels (8)
5		Protozoan of ever-changing shape (6)
10		Yellowish or brownish-yellow spot on the skin especially of fair- haired people (7)
11		Vehicle manufacturer that launched the first production sedan car (7)
12		Surname of the German painter and sculptor who invented the technique of pencil rubbings on canvas, known as frottage (5)
13		World's first university museum (9)
14		Cocktail consisting of vodka, Kahlúa and milk (5,7)
18		Singer who duetted with Diana Ross on the single Endless Love in 1981 (6,6)
21		The Little Bear constellation (4,5)
23		Diacritical sign used over the letter n in Spanish to indicate the sound ny (5)
24		Black vulcanized rubber (7)
25		In an uncertain or intermediate state (2,5)
26		In university slang, a non- collegiate student (6)
27		Winning horse in the 1981 Grand National, ridden by Bob Champion (8)

1		Surname of the designer of the building which was the highest in the world from 1889 to 1930 (6)
2		Small, usually scaleless fish, with comb-like teeth, which inhabit rocky shores (6)
3		Body of water on the Nevada- California border which contains Fannette Island (4,5)
4		English actor who starred in the TV series The Men from Shiloh (7,7)
6		Term given to British mountains over 3000 feet, named after the Scottish climber who originally listed them (5)
7		Strong coarse brandy, literally 'water of life' in French (3,2,3)
8		Wall built across southern Scotland to mark the frontier of the Roman province of Britain (8)
9		President of the National Union of Mineworkers 1981-2002 (6,8)
15		Spark, hint, trace (9)
16		Surname of the French novelist who wrote Madame Bovary in 1857 (8)
17		Hard wheat semolina (8)
19		Former pupils or students (6)
20		Oil distilled from orange flowers, reputedly named from its discoverer, an Italian princess (6)
22		Tall cereal grass, also called Indian corn (5)