What is the average height of men in the UK?

Answer:

The average male height in the UK is 177.8cm ( 5'10") (http://en.wikipedia.org/wiki/Human_height) sampled from males aged 16-24 in 2007.

Using the full age spread of the population in 2002 the guardian quotes a reserach paper (http://www.guardian.co.uk/uk/2002/aug/28/science.research) as being 1,755.1mm (5ft 9in). This makes UK males the second tallest in Europe - second to the Dutch ( 1,795mm)

Figures for the individual countries of the United Kingdom do not seem to be available. Traditionally the Welsh have been somewhat shorter.