More than three million samples have been added to the national DNA database - more than 5 per cent of the population. With new figures showing just 1 per cent of Americans have their genetic information on record, and an average of 0.3 per cent in other European Union countries, ministers were last night accused of attempting to build a national DNA database by stealth.

The last Tory government established the database, the first in the world, when Michael Howard was home secretary but the principle has been enthusiastically pursued by Labour.

Three years ago, police were given the right to obtain and retain DNA samples from anyone arrested, regardless of whether they are eventually convicted. The genetic information remains on file for a person's life and is almost impossible to remove.

The legislation received very little publicity at the time because it was announced on the second day of the Iraq war. Since then, police have doubled the size of the database to 3.1 million. The database is predicted to grow by at least another million by 2008.

Norman Baker, the Liberal Democrat MP for Lewes, who obtained the figures, said: "This is a constitutional outrage - the Government seems to be seeking to create a national DNA database by stealth as a way of catching criminals. If they want to do that, they should come clean and say that is the case.

"This, once again, demonstrates they are illiberal and take a very cavalier approach to civil liberties."

The database is thought to include the majority of the criminal population in Britain. But answers to Parliamentary questions show that nearly 125,000 people on the database have neither been charged nor cautioned for any offence.

Questions about discrimination were also raised yesterday after figures showed that nearly a quarter of those neither charged or convicted were from an ethnic minority.

Overall, 24 per cent of people on the database are non-white, even though the black and Asian population of the UK as a whole is less than 8 per cent. Some estimates have even suggested that that more than a one-third of young black men have had samples taken.

It has already emerged that the DNA profiles of about 24,000 children and young people aged 10 to 18 are stored on the database despite them never having been cautioned, charged or convicted of an offence.

The Home Office argues that serious offences have been solved using the database, and says names will only be taken off in "exceptional circumstances". Philippa Jones, a Birmingham teacher accused of hitting a pupil with a ruler but never prosecuted, fought a long legal battle to have her DNA sample removed.

GeneWatch UK, an independent genetic research group, last night called for ministers to order the destruction of DNA samples of innocent people.

Helen Wallace, its deputy director, said: "Once this data is kept, it's really only one or two steps from being made available to a wide range of people."

The biggest databases

Population/Total(%)/Proportion

United Kingdom 59.8m/3,130,429/5.23

Austria 8.1m/84,379/1.04

United States 298.4m/2,941,206/0.99

Switzerland 7.4m/69,019/0.94

Finland 5.2m/32,805/0.63

Estonia 1.5m/7,414/0.49

Germany 82.4m/366,249/0.44

Slovenia 2m/5,782/0.29

Hungary 10.2m/28,278/0.28

Canada 32.3m/75,138/0.23

Croatia 4.6m/10,744/0.23

France 59.3m/119,612/0.20

Norway 4.5m/6,745/0.15

Netherlands 16.1m/14,747/0.09

Belgium 10.4m/4,583/0.04

Sweden 9m/6,115/0.07

Denmark 5.5m/4,084/0.07

Spain 40.4m/2,656/0.01

Portugal 10.3m/0/0.00

Source: Home Office