Five million Roman Catholics living in England and Wales have been urged to write to their MPs in opposition to plans to redefine marriage.
Archbishop Vincent Nichols, leader of the Church in England and Wales, told Roman Catholics to write “as soon as possible”, outlining their concerns “clearly, calmly and forcefully”.
If the law of marriage changes, the Archbishop says, school children will no longer be taught about the “true nature of marriage”.
The Government has vowed to introduce a Bill to Parliament later this month, but is under intense pressure to abandon the plans.
So far, at least 130 Tory MPs say they will vote against such a Bill, and that number is expected to grow.
The Archbishop wrote to all parishes in England and Wales calling on Roman Catholics to lobby their MPs.
In his letter the Archbishop said politicians should “resist the proposed redefining of marriage with all its likely consequences particularly in schools and in how children are taught about the true nature of marriage”.
He continued: “At this time, we look to our Members of Parliament to defend, not change, the bond of man and woman in marriage as the essential element of the vision of the family.
“I urge everyone who cares about upholding the meaning of marriage in civil law to make their views known to their Members of Parliament, clearly, calmly and forcefully.”
The Government’s official consultation on the proposals has been widely criticised as a sham.
It ignored the names and addresses of 500,000 UK residents who are opposed to the plans, but it included 137,000 anonymous submissions which could have come from anywhere in the world.