High levels of immigration can also make government data unreliable, says Kevin Deardorff, of the American census office.

ECONOMIST: Censuses

In some cases, the Census Office did not release an estimate for these two figures due to trouble with reporting.

FORBES: Magazine Article

According to a specimen 2011 census on the Office for National Statistics website, they will also ask about "same sex civil partnership status" for the first time.

BBC: 2011 census questions published

In December the Government Accountability Office noted that the census's cost has on average doubled each decade since 1970.

ECONOMIST: Censuses

Len Cook, head of the office that does the census, says that estimates of a 250, 000 yearly net outflow were more than 50, 000 short over the past decade, added to which the 1991 census overcounted by more than 300, 000.

ECONOMIST: Holes in the census

The motion said the census will be flawed as a result and attacks the Office of National Statistics (ONS) for "lack of consultation" and "arrogance" in refusing to amend the form.

BBC: Census graphics

The Office for National Statistics has defended the wording of the census.

BBC: Two-thirds of Britons not religious, suggests survey

By last count, no fewer than 106 federal agencies are tasked with gathering statistics, the most important being the Bureau of Labor Statistics, Bureau of Economic Analysis, Census Bureau, U.S. Treasury, Internal Revenue Services, Office of Management and Budget, and Economics and Statistics Administration.

FORBES: It's Time For A Transparency-In-Government-Statistics Law

When asked to respond to Prof Matras's claims, a spokeswoman for the Office for National Statistics said the data published was what had been collected on the census forms for the city.

BBC: Census data on languages in Manchester is 'way out'

The Office for National Statistics confirmed in 2008 a Welsh tick box would be included in the 2011 census.

BBC: Welsh rugby fans