A petition launched last month in opposition to the British government's plans to redefine marriage has been signed by 300,000 people.
The Coalition for Marriage (C4M), the group behind the marriage petition, has described the government's plan as "undemocratic" and said that the consultation launched this month was a "sham."
The British government has faced strong criticism over its plans from Church leaders and pro-family groups.
Although it launched a consultation to hear public views, it stated at the time that its intention was not to decide whether marriage should be redefined to include same-sex couples, but to ascertain how the change should be implemented.
Colin Hart, C4M campaign director, said the huge numbers of people signing the petition was further evidence that the government plans to redefine marriage are wrong and should be scrapped.
"There has been a staggering response to the C4M petition, launched last month, which shows just how many ordinary men and women care about this issue. What has been particularly interesting is the jump in numbers backing the petition since the government unveiled its sham consultation," said Hart.
"I hope the government will consider the growing opposition to their proposals which are being pushed without the British people being given an opportunity to make their views clear.
"The Equalities Minister, who launched the government consultation, has already made it clear that she will not listen to those who oppose the redefinition of marriage."
Their cause has been given a further boost after the European Court of Human Rights issued a ruling calling into question the legal basis of the government's arguments for making the change.
The Court ruled that Article 12 of the European Convention on Human Rights pertaining to the right of men and women to marry should not be interpreted to mean marriage between people of the same sex.
Hart continued, "There is no need to redefine marriage as civil partnerships already give all the legal rights of marriage to same sex couples.
"Redefining marriage would have all sorts of unintended consequences as the institution of marriage is woven into 800 years of our laws, history, education system and culture."