A judge rules today on the High Court damages action brought by MP Chris Huhne's partner Carina Trimingham.
Ms Trimingham's affair with the former secretary of state for energy and climate change became public in June 2010, with Mr Huhne leaving his wife of 26 years.
Ms Trimingham sued Associated Newspapers for misuse of private information and harassment.
She wants compensation and an injunction over 65 "highly unpleasant and hurtful" articles which have appeared since then.
Last month, her lawyers told Mr Justice Tugendhat, at London's High Court, that they constituted a "cataclysmic interference" with the 44-year-old PR adviser's private life.
Associated has contested the case on the basis that there was an important public interest.
Ms Trimingham's counsel, Matthew Ryder QC, said that the Daily Mail had a right to freedom of expression but not to abuse her repeatedly under the guise of exercising that freedom.
The articles had referred to the "life and very different loves of the PR girl in Doc Martens", described her as a "comedy lesbian from central casting", and published an "inherently private" photo of her 2007 civil partnership ceremony.
But the newspaper's QC, Antony White, said their focus was Mr Huhne, and Ms Trimingham's relevance was her role in the Eastleigh MP's marital breakdown, which set off the "after-shocks" they dealt with.
"She is properly in the news because she is relevant to a story about Mr Huhne."