Not all parents would wish to send their children to a Catholic school, even with outstanding results.

It is a strange situation that if you happen to belong to the correct church in a particular area you get priority over other local children, while no counter-policies exist to allow Atheists (or other religions) to receive priority in non-church schools.
Perhaps we could have a local Free School with an Atheist ethos, where parents have to demonstrate a lack of belief in supernatural beings or religious ritual, to get priority entry.

Breaking down barriers between communities is important for a diverse city like London. That, and inspired by Father Ted, is why my two year old daughter can already say 'ecumenical matter' (proof is now available on Facebook). It is important to indoctrinate them at a young age!