The Prime Minister David Cameron attempted today to reassure Christian groups that there were no threats to religious beliefs in extending civil marriage to same-sex couples, during an Easter reception at Downing Street.

He began his speech on a conciliatory note, welcoming what he described as a “fightback” on the part of the Christian faith against “secular attempts” to remove faith from the public sphere—a move immediately denounced by the National Secular Society.

In offering what he described as a “plea” to assembled church ministers and devout politicians, he said: “I hope we won’t fall out too much over gay marriage… There’ll be some strong arguments and some strong words.”

The ruling coalition, with support from Labour, launched a consultation last month to investigate “how” (rather than “if”) to extend civil marriages to gay couples. The move has been denounced by traditionalist religious groups, including Muslims and Sikhs, and some Tory backbenchers. That said, several liberal religious groups have also spoken out in favour of the proposals.

Today, the Prime Minister sought to emphasise to the opponents that the proposals would “change what happens in a register office, not what happens in a church.” But, according to the Telegraph, guests at the reception were not satisfied. Many felt that he was wrong to be promoting such reforms as the legal definition of marriage, in their opinion, should remain that of a union between a man and a woman.

Mr Cameron also referred to the recent series of court cases, where secularists triumphed over Christians, and which prompted the former Archbishop of Canterbury, Lord Carey, to express his fear that Anglican values were being airbrushed from public life. The government’s response has been, he said, to change the law to reinstate the right of councillors to hold prayers.

“I think there’s something of a fightback going on, and we should welcome that,” Mr Cameron added. “The values of the Bible, the values of Christianity are the values that we need.” His official Easter message, separately released today, echoed similar sentiments.