UK: Practising Muslims 'will outnumber Christians by 2035'
The figures are published in the latest in a series of reports entitled Religious Trends.
The think-tank has warned that 4,000 churches could close by 2020 if congregations continue to shrink at current rates.
According to the most recent figures from the Church of England, regular Sunday, weekly and monthly attendance each fell by one per cent in 2006.
Fewer than a million people attend church every Sunday.