Security agency MI5 has been heavily criticised over the way in which it handles and stores confidential data.
In documents disclosed as part of a High Court hearing, investigatory powers commissioner Sir Adrian Fulford said the organisation is currently failing to comply with relevant legislation and has "inadequate control" over its file-sharing and databases.
"I consider that MI5's use of warranted data are currently, in effect, in 'special measures', and the historical lack of compliance … is of such gravity that the Investigatory Powers Commissioner's Office will need to be satisfied to a greater degree than usual that it is 'fit for purpose'," he added.
In another document, even MI5's director for policy, compliance, security and information admitted that personal data being collected is sometimes stores in 'ungoverned spaces'.
There is strong legislation in place determining how security agencies handle and store data, which includes guidelines on to whom information is made available and the extent to which material is disclosed to unauthorised individuals.
The revelations come a month after home secretary Sajid Javid criticised MI5 for potential failures in safeguarding information, while civil rights group Liberty has long argued that MI5, MI6 and GCHQ all have 'unwarranted' data retention powers.