Transparency laws should be widened in Northern Ireland to allow examination of the DUP's alleged links to data firm Cambridge Analytica, ministers have been told.
The call came after Sinn Fein wrote to the Information Commissioner's Office over the unionist party's alleged links with the company - which is at the centre of a scandal over the harvesting and storing of social media users' data.
Liberal Democrat MP Layla Moran (Oxford West and Abingdon), speaking in the Commons, told ministers that transparency rules needed to be widened for "full disclosure".
The Government announced last year that it would bring into force new transparency rules for Northern Ireland's political parties to allow the Electoral Commission to publish details of donations over £7,500.
However rules would only apply to donations from July 1 2017 - not 2014, as in the rest of the UK.
Ms Moran said: "It's been recently revealed that a portion of the largest ever political donation given to a party in Northern Ireland was spent on services linked to Cambridge Analytica.
"In light of this, shouldn't the Secretary of State backdate transparency regulations to 2014 so we can finally get full disclosure about where that cash came from?"
Northern Ireland Secretary Karen Bradley said the decision to backdate transparency rules was "taken on the basis of broad support from the majority of political parties in Northern Ireland".
Independent MP Lady Hermon (North Down) later asked why the decision was taken to backdate to 2017 and not 2014.
She said: "I'm really very interested to hear the explanation from the Secretary of State why the Northern Ireland office deliberately, wilfully, ignored the advice and recommendations of the Electoral Commission that the publication of donations to political parties in Northern Ireland should be backdated to 2014, not 2017."
Ms Bradley responded: "There was no wilful ignoring or anything else; my predecessor consulted with all the parties in Northern Ireland and there was broad support for 2017."