Aaqil Ahmed warned there was a rise in the number of Christians with "conflicting views" on issues like homosexuality.
"How do we deal with this?" He asked.
Writing in the Independent he said Britain would have to look at the lack of understanding of faith if it was to accommodate immigrants coming to the country who practice "more assertive" Christianity.
He cited the arrival of Africans and the "upsurge in Catholic numbers" from Eastern Europe.
"Christianity may have been pronounced to be at death's door in the last century but now it's firmly back in the public space and how we deal with that is the real battle for Christianity here in the UK," he said.
"If among this growth is a more assertive Christianity with conflicting views with society on homosexuality, for example, then how do we deal with this?"