Blasphemy to me is a potential minor social faux-pas. To Mrs. Stan it's genuinely offensive, and to a sizable number of Muslims, it's justification for killing the infidel. So it's certainly worth knowing your audience before you indulge.
There is a law in this country against blasphemy - Mary Whitehouse tried to use it and Muslims tried to use it against Salman Rushdie. Both failed.
In reality, the last man to do time for blasphemy was John William Gott. In 1922 he was sentenced to nine months' hard labour for comparing Jesus with a circus clown (presumably unfavourably). In Scotland, there has not been a public prosecution since 1843.
The law serves only to protect the established church, so if you're a Methodist, a Catholic or a Jedi - I'm afraid you're fair game.
Help is at hand though, in the shape of Dr. Evan Harris MP who is trying to have the blasphemy laws abolished.
Seems fair to me - blasphemy should something that parents (optionally) deal with. Calling the police shouldn't be an option.
I'm sure that the only reason the Church of England is opposing the removal of this redundant and obsolete law is that they're worried that people might get a taste for removing the redundant and the obsolete from British life.
For example, the Church of England, the Monarchy ...