According to press reports, the Metropolitan police intend to retain indefinitely information recorded from a mobile phone, without judicial authorisation. This will be irrespective of whether an individual is charged or convicted.
Following the ruling in S and Marper v UK  the legal status of indefinitely retaining personal information was made quite clear, and following the passage of the Protection of Freedoms Act it is the case that DNA cannot be retained indefinitely
Trials are now live in 16 London boroughs, and we have written to the ICO to urge them to investigate the Data Protection Law implications of such technology being employed by the police and whether indefinite retention is, as we believe, an infringement of the law.
The courts have clearly said indefinitely retaining personal information is not acceptable and it appears the Met are flagrantly disregarding the law.
Where someone is not convicted of a crime it is absolutely wrong for the police to hang onto the contents of their phone.