A motion was passed on Sunday night which will now stop college officials not allowing religious societies to attend the fair for new students.
The Oxford student newspaper, Cherwell, reported that leaked emails showed discussions between the committee members at Balliol JCR (Junior Common room) and the CU.
Vice President of the Balliol committee, Frederick Potts, who helps organise Freshers' Week, at first prevented the CU to attend because the college wanted it to be a "secular space". He said a CU stall could potentially lead to "harm to freshers".
Jack Hunter and Felix Pope from Cherwell paper, reported that Potts wrote: "We recognise the wonderful advantages in having CU representatives at the Fresher's Fair, but are concerned that there is potential for harm to freshers who are already struggling to feel welcome in Oxford."
His reasons were explained further: "Christianity's influence on many marginalised communities has been damaging in its methods of conversion and rules of practice, and is still used in many places as an excuse for homophobia and certain forms of neo-colonialism."
The JCR have been criticised for "barring the participation of specific faith-based organisations" as a JCR motion was unanimously passed that this would not be allowed again. Their actions were described as "a violation of free speech [and] a violation of religious freedom".
The Universities and Colleges Christian Fellowship (UCCF) have said the matter was amicably resolved. Director of UCCF, Rev Richard Cunningham, said: "We are however concerned that the current desire to provide safe spaces on campus does not infringe on the core liberties of freedom of speech and freedom of association which are surely foundational to the university experience and indeed to basic human flourishing." The CU support charity added that "Most Student Unions [SU] are fair-minded and enjoy a good relationship with the CU in their university."
Vice President Frederick Potts has been invited to comment further.