The UK's data and privacy watchdog is looking into how personal data on the Government's main website is collected after it was reported the portal is being used to target users in preparation for Brexit.
A memo obtained by BuzzFeed allegedly tells departments to share data collected from its gov.uk, marked as "top priority" by the Prime Minister's chief adviser Dominic Cummings.
It claims Boris Johnson informed members of the Exit Operations Committee that the Government Digital Service should "allow targeted and personalised information to be gathered, analysed and fed back actively to support key decision-making".
The Information Commissioner's Office (ICO) said it has "contacted Government regarding the collection of personal data on gov.uk in order to fully understand its approach to compliance with data protection law and whether any further action is necessary".
The portal is the central hub for access to official information and services online, such as renewing passports or advice on being self-employed.
An upturn in people visiting the site is expected, seeking details about Brexit as October 31 looms ever-closer.
It said it wants to bring this anonymised data together under one central roof to improve the service.
Damian Collins, chairman of the Digital, Culture, Media and Sport Committee, said he will be asking Culture Secretary Nicky Morgan about how the Government uses data in communications when she appears in front of MPs on October 16.
Lib Dem MPs wrote to the watchdog expressing concern about the report's allegations, asking for clarity on what the data is used for.
"Will you be seeking to meet with No 10 and the Cabinet Office to confirm any such data transfer or analysis is within the law and in particular that the data will not be used by Government to promote their political agenda or be exported to third-party organisations such as the Conservative Party," they said.