Pro-lifers braved the unpredictable weather in London on Saturday to take their message about the sanctity of life to Westminster.
Parliament Square in front of the House of Commons was packed for the annual March for Life UK, which took place this year under the theme of "Irreplaceable", reflecting the uniqueness of each baby.
The march was joined by Auxiliary Bishop of Westminster John Wilson, who said that protecting the unborn was essential "if we care for our common humanity".
"Friends, we're becoming increasingly aware of the danger of climate change and so we desire to become better stewards of creation by caring for the earth," he said.
"We do this authentically only if at the same time we are stewards of human life.
"If we work for the extinction of life, we are not working for the beauty of creation."
Antonia Tully, of the Society for the Protection of Unborn Children, said that the fight for policy change in Parliament could only be won if there was a change in attitude towards abortion in society.
"We will not change the law in Westminster until we change hearts and minds up and down the country," she said, adding, "The devastation that abortion causes women is something we cannot ignore."
March for Life has been taking place in the UK each year since 2012. Last year was the first time that the march was held in London after starting out in Birmingham.
Keynote speakers this year included abortion survivor Melissa Ohden and Jennifer Christie, who kept her baby after becoming pregnant as the result of a brutal rape.
Ms Ohden told the crowds: "I am standing here with you today as a wife, a mother, a daughter, a sister, a Master's level prepared social worker, and yes, as an abortion survivor. You would never tell by looking at me today, but 41 years ago, I survived a 'failed' saline infusion abortion.
"In my work as the founder of The Abortion Survivors Network, I have had contact with 286 other abortion survivors, including five from the UK, four of whom are still alive today.
"Despite the miracle of my survival, the doctor's prognosis for my life was initially very poor. My adoptive parents were told that I would suffer from multiple disabilities throughout my life. However, here I am today, perfectly healthy.
"Whether I had lived with the expected disabilities or not, my life still deserved to be protected and respected, I still was worthy of the love that my family freely offered.
President of Culture of Life Africa Obianuju Ekeocha said: "I am here to lament about the human rights issue of our time. Abortion in this country has been legal now for more than 50 years and has taken the lives of more than nine million people.
"We are all gathered here today in this special venue because we have come to raise our voices to this parliament, because this parliament has it wrong."
March for Life UK said the turnout on the day was in the thousands.
Speaking to Christian Today ahead of this year's march, co-director Isabel Vaughan-Spruce, said the theme of "Irreplaceable" was a reminder "that each human being from the moment of his or her conception is a unique individual that cannot be replaced by any other human being".
She said that the March for Life was about changing attitudes and not just the law.
"We make no secret of the fact that we would love abortion to be illegal since a civilised country should not support the killing of it's own children but clearly more than that is needed," she said.
"We need to make abortion unthinkable and for there to be sufficient support and encouragement for mothers/couples so that children aren't thought of as burdens and for adoption to be presented in a more positive light."