Via the Guardian:
The head of the Muslim Council for Wales says many Muslims in the city were fearful of filling out the census in 2001 and is urging the to fill out their census this weekend. Daniel Hewitt and Paul Heaney report
An Islamic organisation in Wales has said that some Muslims in Cardiff are fearful of filling in their census forms.
Saleem Kidwai, head of the Muslim Council for Wales, believes up to 20,000 Muslims living in Cardiff didn't state their religion in 2001.
Saleem Kidwai says in this interview Muslims in Cardiff should fill out their census forms to receive resource benefits for the whole community Link to this audio
However, the last census suggested there were 11,000 people in Cardiff who described themselves as Muslim.
Kidwai said:
"People were apprehensive about filling in the forms, particularly the religious section of it, not knowing for what purpose the information would be used."
"It is vitally important that they tick that box because only then will we know the number of Muslims in this country and accordingly, the resources are allocated."
(source)