Only 60 per cent of the 650 MPs sworn in at Westminster this week chose to swear a religious oath.
The number reflects the result of the 2021 census which showed 65 per cent of adults across the UK have a religious affiliation.
338 MPs swore on the Bible, 14 on the Quran and 3 on the Bhagavad Gita, the Hindu scripture.
The figures, compiled by Humanists UK, show the remaining 40 per cent, around 249 MPs, made an affirmation without reference to God.
In 2019, 24 per cent of all MPs chose the non-religion affirmation.
Members of both Houses of Parliament are required by law to take an oath of allegiance to the Crown. They can't take their seat, speak in debates, vote or receive a salary until taking the oath or affirmation. They could also be fined £500 and have their seat declared vacant “as if they were dead” if they attempted to do so.
Graham Nicholls is director of Affinity which is a network of 1,200 evangelical churches and ministries in the UK. He told Premier many people don't realise Christian values underpin our Parliament and society:
"I think it's exciting that there are lots of new Members of Parliament and hopefully they're enthusiastic. We want to pray for them that they operate with integrity and wisdom. So whatever your political leanings and who you supported, I think it's good to get behind the new Parliament and the new government and support them.
"I respect the integrity of those who don't want to swear on a Bible, because that wouldn't have integrity because they don't believe in God. So in a sense, it's a positive thing. But it's a sad thing that lots and lots of people actively don't want to have anything to do with God or our Christian history in this country.
"I think many people don't recognize the Christian roots of many things that happened, both in Parliament, but also in lots of the other institutions and in law that all come from our Christian heritage.
"That people don't believe in Jesus is the ultimate sadness, but it's also sad that they don't realize about our history and how they're influenced by Christian history. It's Christian heritage that's making them think truth is important."
MPs take the oath by holding the sacred text in their uplifted hand and saying the words of the oath:
I swear by Almighty God that I will be faithful and bear true allegiance to His Majesty King Charles, his heirs and successors, according to law. So help me God.
The Act also permits the oath to be taken in the Scottish manner. With uplifted hand but not holding the sacred text. Members may also take the oath by kissing the book and using the words:
I do swear that I will be faithful and bear true allegiance to His Majesty King Charles, his heirs and successors, according to law. So help me God.