Atheists and secularists are calling on the international community to act to reverse a growing trend of persecution of the non-religious.

Humanists in the UK are working closely with the Foreign and Commonwealth Office in the UK to ensure the issue of the persecution of atheists is high on the agenda.

The problems faced by non-believers in parts of the world were highlighted when a high-profile prominent atheist blogger was hacked to death in Dhaka last month.

The blogger's wife accused police of merely standing by while murderers attacked the couple with machetes.

Rafida Bonya Ahmed, who lost a finger and suffered head injuries in the killing of Bangladeshi-American Avijit Roy after the couple were returning from a book fair, called on the Bangladeshi government to do everything possible to bring them to justice.

"While Avijit and I were being ruthlessly attacked, the local police stood by and did not act," she told Reuters. She added that the government should "stop a legal culture of impunity, where writers can be killed without the killers being brought to trial."

The FBI is helping with the investigation into the attack and her claims.

Roy, founder of the Mukto-Mona or "free mind" blog site, had received threats after posts in which he offered secular interpretations on science and social affairs and which were criticised for being anti-Islam.

He was the second Bangladeshi blogger murdered in that last two years. A further two writers have also been attacked in recent years.

In Saudi Arabia the blogger Raif Badawi, who was sentenced to 1,000 lashes over accusations he insulted Islam, is now facing possible trial for apostasy which could lead to a death sentence. Badawi, 31, who founded the website Free Saudi Liberals and is currently in jail for ten years, was so seriously injured after the first 50 lashes that the rest of the floggings were postponed.

Recently in Egypt, the atheist Karim al-Banna was given a three-year jail sentence for "insulting" Islam with his atheism. He has said he would like to live anywhere Egypt.

"All I want now is to leave Egypt. Life is not possible for atheists here," the 23-year-old engineering student told AFP.

And in Turkey, a website belonging to the country's first official atheist association has been judged to be an "insult to religious values" and blocked by a court in Ankara. The ruling cited Turkish Penal law which forbids "provoking the people for hate and enmity or degrading them."

A recent 540-page report found that most countries fail to respect the rights of atheists and freethinkers.

The Freedom of Thought report by the International Humanist and Ethical Union, published a few weeks ago, found non-religious people are being targeted by "hate campaigns" in countries around the world.

The report found that the "hate speech" against atheists did not come exclusively from reactionary or radical religious leaders, but increasingly from political leaders, including heads of state.

In addition to laws against "apostasy" and "blasphemy", there was in 2014 a big increase in specific targeting of "atheists" and "humanism".

Cases covered included the Malaysian Prime Minister Najib Razak, who labelled humanism, secularism and liberalism as "deviant" and a threat to Islam and the state itself.

Saudi Arabia was criticised in the report for a new law that equates "atheism" with "terrorism". Saudi's new terror regulations explicitly ban the crime of "calling for atheist thought in any form, or calling into question the fundamentals of the Islamic religion."

Egypt was found to target atheists directly in "an organized backlash against young atheists." Thirteen Islamic states have the death penalty for "apostates".

The report cites a survey in 2012 that found that six out of ten people in the world are religious, while 13 per cent are atheist and a further 23 per cent non-religious. Article 18 of the Universal Declaration of Human Rights states that everyone has the right to freedom of thought, conscience and religion.

Andrew Copson, chief executive of the British Humanist Association, said: "In recent years we have seen a growing trend of persecution of the non-religious globally, from Raif Badawi's 1,000 lashes, to the recent murder of Bangladeshi-American blogger Avijit Roy, and it is urgent that the international community takes action to reverse this trend. We have been working increasingly closely with the UK Government's Foreign Office in order to ensure that this issue is high on their agenda, and are proud to be supporting the new End Blasphemy Laws campaign, which aims to repeal blasphemy laws worldwide.

"Even here in the UK, however, the non-religious face discrimination and special privileges are afforded to religious groups. It would be unthinkable for hospitals to be organised along ethnic lines, or for public transport to be segregated by gender, and yet one in six state school places in England first prioritise those of a certain faith, then prioritise those of other faiths, before finally, if space is left, admitting those of no faith. This discrimination has to stop."

Keith Porteous Wood of the National Secular Society said that belonging to the "wrong" kind of Islam is potentially life threatening, and religious tolerance in Muslim countries has now almost disappeared, from being relatively widespread 20 or more years ago.

"Wahhabism is certainly more widespread, and well funded. Few, if any, Muslim majority countries uphold people's right to renounce or change their faith. An accusation of blasphemy against someone in Pakistan is likely to lead to death threats and possibly death in prison. The mullahs so intimidate the courts and lawyers and judiciary that obtaining a fair trial is difficult and sometimes impossible. Even worse is that often the charges are baseless, an easy way of eliminating political or business rivals."