The number of crimes solved thanks to the DNA database is actually falling despite the ever-growing number of people it contains.
Figures given to Parliament show that even though 7 per cent of the UK population are now on the DNA database it helped solve only 0.36 per cent of crimes, down from 0.37 per cent last year. In the same period over half a million people have been added to the database.
In fact there has been no big improvement in convictions since 2000/2001 when the database contained just 1.2 million people but was useful in 0.29 per cent of recorded crimes.
There are 4.7 million records on the English and Welsh database relating to some 4.1 million individuals. In 2007/2008 another 541,000 individuals were added to the database, down from 667,000 the year before.
In 2007/2008 DNA played a useful role in tackling 17,614 crimes out of a total of 4,950,671 crimes recorded. The database cost £1.6m to run last year, down from £2.04m in 2006/2007.
Parliament also got a breakdown of the ethnic appearance and ages of those on the database. It's thought that replication of records means the total number of entries is 13.3 per cent higher than the number of people these records relate to.
There are 80 children aged under ten with DNA records. There are 325,422 DNA records for people of black appearance, 226,938 for people of Asian appearance, 26,300 for people of Chinese, Japanese or south east Asian and 3,294,760 records for people of northern European appearance.
There are just under a million children aged between 10 and 17 on the database - 917,252.
A Home Office spokeswoman said: "The National DNA Database (NDNAD) is a key intelligence tool which has revolutionised the way the police can protect the public through identifying offenders and securing more convictions.
"The benefits of the NDNAD lie not only in detecting the guilty but in eliminating the innocent from inquiries, focusing the direction of inquiries resulting in savings in police time and in building public confidence that elusive offenders may be detected and brought to justice.”