sorry - mistake- Newtonhall is supposed to be the biggest PRIVATE estate in Europe.
As for council estates, what about some the Glasgow ones such as Drumchapel?
According to "Ask Jeeves", the following estates either claim to be the current biggest, or have calimed to be the biggest in the last few years:
Clifton - Nottingham
Pennywell- Sunderland
Becontree - Dagenham
Bransholme - Hull
Easterhouse - Glasgow
Leigh Park- Portsmouth