There have been loads of threads in the past about the 50% cap on faith-based admissions, which has applied to all the new faith academies and free schools established since 2010. If you're not familiar with it then there's a good Wikipedia article here which gives a lot of background: en.wikipedia.org/wiki/The_50%25_Rule
Theresa May's manifesto said that she would ignore the responses to the Schools That Work for Everyone consultation and remove the cap, but it's all gone very quiet since she was elected(ish).
A decision is expected soon, and a cross-party group of MPs has started an Early Day Motion (which is a sort of petition for MPs) to say it should be kept. MPs need to be prodded to sign EDMs by their constituents, so if you feel strongly on this, now is a good time to write to them. If you don't have time to write your own letter then the Accord Coalition (campaign group) has made it easy by setting up a template letter: accordcoalition.org.uk/2017/11/10/mps-urge-government-not-to-jettison-anti-discrimination-cap-at-faith-schools/.
Either way it's going to be really interesting to see how the Government proceeds on this, because there is pretty good evidence that the cap is doing the job it was intended to do, and is popular with the vast majority parents. (I know many people out there think it should go further and ban faith-based admissions altogether, but if even this small and unprecedented step in the right direction can't survive a change in government there's little hope for further reform in future).