7m census 'dodgers' face knock on the door

Seven million households which have failed to fill in and return the census in England and Wales are being warned that they face a knock on the door from officials.

An army of 29,000 census collectors will begin house-to-house calls chasing people who have not yet filled in and returned their questionnaire.

They will be helping, and in some cases persuading, householders who have so far been reluctant or too busy to fill in their forms, the Office for National Statistics (ONS) said.

Nearly three-quarters of households have completed and returned the forms, with the North East region leading the way at 75% compliance, while London trails in last place with a total of only 60%.

The ONS said it had anticipated that London would be a "challenging area" and almost 6,000 collectors would be devoted to door-knocking in the capital.

Around 26 million households in England and Wales were sent the questionnaire last month to fill out on March 27, or as soon as possible afterwards.

Glen Watson, 2011 Census director, said: "I am pleased that nearly three-quarters of the forms have come back just nine days after Census Day.

"Collectors are all set to start work at 2pm today to collect questionnaires from households who haven't sent theirs back or completed the census online."

Filling out the census is compulsory with the threat of a fine of up to £1,000 if a questionnaire is not completed and returned.

But the ONS has said legal action will only be taken where people persistently refuse to complete a questionnaire.

* All 2011 Census field staff will be wearing photo identification badges and carrying other "visibly branded" items, the ONS said.

If anyone is unsure about the identity of anyone claiming to be from the census, they should ask to see their proof of identity before answering any questions.

If they are still concerned they should contact the census helpline on 0300 0201101 in England or the Welsh helpline on 0300 0201130.