Britain's DNA database is being built by stealth, critics warned, as the Government admitted record numbers of profiles were added last year.
Many of the 722,464 new samples were taken by police from people who have never been convicted of – or even charged with – a criminal offence.
The total number of DNA profiles held is estimated to be about 4.8 million. Some 350,000 of those taken last year were from children aged 14 and under.
Chris Huhne, the Liberal Democrat home affairs spokesman, said: "The Government is rapidly building the world's biggest DNA database, by stealth. Guilt or innocence and the negative effect the database has on children and ethnic minorities are of no concern to ministers."