Conscience has a right to freedom. For centuries, as churches attempted to force on men Christ's work with the methods of Herod, the rights of those whose consciences rejected such teaching were often lost on the rack and in the faggot pyres. Post Enlightenment, we recognise the rights of individual conscience of all those who choose not to take the teaching of Christ, but we're now in danger of imperilling the consciences of those that do.
A valid act of faith is a choice interior to man; we can sign a contract, join a firing-squad, pronounce an oath of allegiance all without any interior consent, but unwilling belief is an impossibility. Our bodies may serve Caesar, but our souls are God's.
No Christian need be under any obligation to heed the assumptions behind Harman's Equalities Bill in so far as these violate the sanctity of individual conscience and faith; being true to one's conscience is one of the greatest duties we owe to our interior selves, and this is not a realm where Caesar has any authority.