A key part of the government's counter-terrorism strategy, Prevent, is to face a legal challenge in the High Court on Tuesday.
Salman Butt, a British Muslim activist, has launched legal action, saying he was named as a "non-violent extremist" by the government.
He says aspects of Prevent breach free speech rights.
The Home Office has accused Dr Butt of expressing views that violate British values, something Mr Butt denies.
A Home Office spokesman said: "It would be inappropriate to comment on ongoing legal proceedings."