Equal, the Campaign for Equal Marriage in the Church of England, want same-gender couples to be able to get married in parishes across the country.
Rev Andrew Foreshew-Cain, one of the team members leading the campaign, told Premier the significance behind Friday's launch date.
"Today is the fifth anniversary of the wedding of Cannon Jeremy Pemberton to Laurence Cunnington - the first marriage of a Church of England priest to a same-sex partner.
"On their anniversary day, we thought we would launch the campaign, congratulate them on their happy marriage and to celebrate all the marriages that have been made possible since the change in the law."
The group says the "consciences of everyone should be protected" and "no member of the clergy should be forced to conduct a marriage they disagree with, but also no member of the clergy should be prevented from celebrating a marriage involving a same-gender couple".
However, the Coalition of Marriage, which supports traditional marriage and opposes its redefinition, thinks the campaign will have the opposite effect.
Colin Hart, the group's chairman told Premier: "It will destroy the freedoms of everybody else.
"The problem is this - although that's not what they intend, it will completely smash the 'quad lock' to smithereens.
"The reason for that is, the Church of England is the state Church and is particularly vulnerable to being sued under human rights."
'Quad-lock' safeguards give clergy an absolute right to refuse to conduct same-sex weddings.
The Campaign's logo could easily be mistaken for The Church of England's but the group is actually an independent group.
Rev Foreshew-Cain told Premier the logo was intended to look like the Church's.
"The campaign is by and for Church of England people. We are faithful members of the Church of England, campaigning within it for a change in its official stance.
"So it's to show that we are part of the Church of England as everybody is."
A spokesperson for the Church of England told Premier in a statement: "The Church of England seeks to be a place of welcome to people from all backgrounds, irrespective of sexuality or gender.
"The Church's position is that marriage is between one woman and one man. However, the Church of England is aware of the different and deeply held views about same sex marriage among its members.
"The Living in Love and Faith process is producing resources that will enable the Church to reflect on this position while listening to and gathering the stories and perspectives of many individuals who represent this wide range of views and lived experiences."
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