The trial of Andy Stephenson and Kathryn Sloane got underway yesterday and will continue until next week.
The pair belong to the Abort67 campaign group and were arrested last year for showing images of aborted babies during a peaceful demonstration outside Wistons BPAS abortion clinic.
The images were deemed to be in breach of section 5 of the Public Order Act, which criminalises causing harrassment, alarm or distress to the public.
It was the first time police took action against members of the group, which had been protesting outside the clinic for five years.
Stephenson and Sloane are being supported by the Christian Legal Centre.
CLC chief executive Andrea Minichiello Williams said: “This is a crucial test case for freedom of speech on the issue of abortion.
“The pictures are distressing because abortion is distressing.
“Freedom of speech is one of our most precious freedoms. If we limit discussion of abortion we are censoring a critical debate on an issue which affects hundreds of thousands of lives.”