The UK National Hi-Tech Crime Unit (NHTCU) has asked internet service providers (ISPs) and telcos to keep records of events last week for another month.
The unit has reiterated that it is not looking for specific information, but that the measure is a precaution in case it could help US investigators.
The NHTCU has asked ISPs only for email logs, not their content, but has asked for the content of voicemails and SMS text messages to be kept.
UK Data Protection laws mean that only those records needed for billing purposes are kept for longer than 48 hours, prompting the NHTCU's request that those records not already destroyed should be retained.
The NHTCU has asked ISPs and phone operators to hold records relating to 11 September for a month, after which time the position will be reviewed.
Although not required to do so by law, UK ISPs are likely to put aside their general objections to retaining data records and comply with the request.
Should they refuse, the police would be forced to try and obtain a court order under Exemption 29 of the Data Protection Act, to compel them.
Data records retention is currently subject to fierce debate in both the UK and Europe. Indeed it has split Brussels, with European Union (EU) ministers and European Commission (EC) officials adopting opposing positions.
EU ministers are backing law enforcement authorities' demands to extend laws to aid criminal investigations, while the EC supports the position of civil rights groups and carriers/ISPs, which have argued that current laws suffice and that the proposed extensions go too far.
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