The High Court in Belfast has been told that the Omagh bomb could and should have been prevented.
Lawyers for Michael Gallagher whose son was killed in the blast claimed there was enough intelligence available ahead of the terror strike.
Michael Gallagher is seeking to judicially review Northern Ireland Secretary Theresa Villiers over her decision to rule out a public inquiry into the Real IRA attack.
A decision is expected in the coming weeks.
Speaking today, Michael Gallagher says a case may also be taken in then republic: