The Newnham policy linked to above claims:
Schedule 12 of the Equality Act 2010 allows Newnham as a single sex higher education institution exceptionally to admit ‘students of the opposite sex.’
Newnham has decided to continue exceptionally to accept applications from the small number of students who identify as transwomen and hold ID (passport, driving licence or gender recognition certificate) in the female gender.
https://newn.cam.ac.uk/sites/default/files/2025-10/rationale.pdf
Schedule 12 of the EA applies to places of Further and Higher Education:
Admission to single-sex institutions
1(1)Section 91(1), so far as relating to sex, does not apply in relation to a single-sex institution.
(2)A single-sex institution is an institution to which section 91 applies, which—
(a)admits students of one sex only, or
(b)on the basis of the assumption in sub-paragraph (3), would be taken to admit students of one sex only.
(3)That assumption is that students of the opposite sex are to be disregarded if—
(a)their admission to the institution is exceptional, or
(b)their numbers are comparatively small and their admission is confined to particular courses or classes.
(4)In the case of an institution which is a single-sex institution by virtue of sub-paragraph (3)(b), section 91(2)(a) to (d), so far as relating to sex, does not prohibit confining students of the same sex to particular courses or classes.
www.legislation.gov.uk/ukpga/2010/15/schedule/12
Section 91 is under Part 6 of the EA covering Education and is specific to the admission and treatment of students:
91Students: admission and treatment, etc.
(1)The responsible body of an institution to which this section applies must not discriminate against a person—
(a)in the arrangements it makes for deciding who is offered admission as a student;
(b)as to the terms on which it offers to admit the person as a student;
(c)by not admitting the person as a student.
(2)The responsible body of such an institution must not discriminate against a student—
(a)in the way it provides education for the student;
(b)in the way it affords the student access to a benefit, facility or service;
(c)by not providing education for the student;
(d)by not affording the student access to a benefit, facility or service;
(e)by excluding the student;
(f)by subjecting the student to any other detriment.
https://www.legislation.gov.uk/ukpga/2010/15/section/91
The Newnham policy goes on to say:
Newnham is satisfied that the exceptional admission of transwomen students does not prejudice its fundamental character as a single-sex higher education institution for women.
In the next para it contradicts thar description of itself as single-sex:
Newnham is not and has never been a single-sex space. Newnham employs male staff in a range of roles. Newnham has also allowed male guests to stay overnight and use communal facilities for at least 45 years.
IANAL but it seems to me that Newnham is saying that it will admit TIM because:
It isn’t allowed to discriminate against candidates under Section 91;
Anyway there aren’t very many TIM so we can do it on an exceptional basis;
And (for good measure) Newnham is single sex but allows male staff and guests in the building so isn’t really single sex anyway, so what’s the difference if we admit TIMs.
I still don’t see how Newnham (we are the oldest college run by women, for women) can call itself a women’s college if it admits trans identifying males though.