Today the government responded to the Marper ruling of the European Court of Human rights, which criticised the permanent retention of the DNA of innocent people. The government announced the retention of innocent DNA for up to 12 years. This is bound to spark further controversy.

What's wrong with the Scottish model? In Scotland, the only innocent DNA retained is on those initially arrested for - but not subsequently convicted of - a serious sexual or violent offence. That exception applies for a limited period of 3 years. This has not hamstrung law enforcement - Scottish detection rates are no lower than in the rest of the UK.

Read the report in the Times.