According to Channel 4 news that I've just watched Christina Odone was 'censored' for insulting atheists. Digging a little deeper reveals her on the Today programme (here around 21 mins in) and this from the New Humanist blog. Odone on the Today programme accuses the guy from the Commonwealth Foundation of "your folly in not allowing somebody of faith to speak at a carol service at Christmas".
But it turns out her speech was for the Commonwealth Foundation carol service in partnership with the Fairtrade Foundation, on the topic of 'opportunity for all' and she decided to use this topic to attack atheists and secularists for oppressing religious believers. So they told her that what she wanted to say would offend non-religious believers attending and asked her to read something else by Bertrand Russell instead, and she refused and pulled out.
Clearly her right to free speech has been suppressed by the evil forces of secularism, and it is not at all the case that she tried to subvert a non-denominational event promoting development goals in order to spread her own particular brand of religious victimhood and atheist bashing.