This petition was rejected

The Government e-Petitions Team gave the following reason:

We are not sure what action you would like Parliament to take.

Your petition states that "Christianity is the official religion in the UK", and asks for this to be reinforced in law. However, the existing situation is not quite as clear as this. The Church of England is the established church in England, the Church of Scotland is the national church in Scotland, reflected in the Act of Union 1707, and there is no established Church in Wales or Northern Ireland. It is not therefore clear what you would like a law to do.

If you could be more specific about the law you would like Parliament to pass, you could submit a new petition asking for that legislation.