European Union ministers have agreed a deal compelling mobile phone companies to retain call and internet records for use in anti-terror investigations.
Charles Clarke has urged Europe to unite on the telecoms issue
Records will kept for up to two years under the new rules, which need to be approved by the European Parliament.
Police would have access to information about calls, text messages and internet data, but not exact call content.
Justice and interior ministers agreed governments can decide how long to hold data, from six months to two years.
The talks in Brussels had stretched into a second day.
The European Parliament had called for information to be disposed of after a year, while EU member states pushed for two.
Danish Justice Minister Lene Espersen praised the deal.
"I am very happy that the EU jointly can send a signal that we take the fight against terrorism very seriously. I have fought against the plans being watered down," she told the Reuters news agency.
According to UK Home Secretary Charles Clarke, data is the "golden thread" in terrorist investigations.
"Without such measures, European states would be fighting terrorism with both hands tied behind our backs," he has previously said.
As the current EU president, the UK had hoped to reach a consensus in all European institutions by the end of its presidency in a few weeks' time.