There is a lot of talk about the squeezed middle in the UK, Is class based mainly on income and if so what is considered to be a middle class salary ?
'Middle class' is an intangible and rather undefined term. 'Middle class' means different things to different people. You can look in the UK census for median household income, but that doesn't mean anything.
The BBC's recent attempt to try and define classes might interest you http://www.bbc.co.uk/news/magazine-22000973