Religious Freedom in the World, compiled by advocacy charity Aid to the Church in Need, assesses the state of persecution every two years.
This is the 13th edition and assesses instances of persecution worldwide between June 2014 and June 2016.
It found freedom to practice Christianity, as well as other faiths, deteriorated in 11 of the 23 worst countries in the world for persecution over the two year period.
Seven others in that group were classed as so bad they could "scarcely get any worse".
The world's worst countries for religious freedom:
Afghanistan
Bangladesh, Burma
China
Eritrea
India, Indonesia, Iraq
Kenya
Libya
Niger, Nigeria
North Korea
Palestinian Territories, Pakistan
Saudi Arabia, Somalia, Sudan, Syria
Tanzania, Turkmenistan
Uzbekistan
Yemen
The report found in 55 countries where there are significant violations of religious freedom, 38 had remained stable, rather than got worse, over the two-year period.
Religious liberty in three of those countries - Bhutan, Egypt and Qatar - improved over that period.
It also cited various examples of persecution, including China tearing down more than 2,000 church crosses (main picture), the murder of 148 people - most of them Christians - at a university in Kenya in 2015, and the murder of an Ahmadiyya Muslim shopkeeper in the UK by another Muslim in 2016.
There were also positive case studies, for example an inter-faith football match in Pakistan. The example was a rare story of interfaith unity amid regular persecution of Christians and other minorities there, including the murder of 70 people on Easter Day by the Taliban at a funfair in Lahore earlier this year.
Another encouraging story came from Morocco, where a landmark Islamic conference was held in January this year openly calling on all Islamic leaders to protect religious minorities.
The conference in Marrakesh, attended by more than 120 countries, also totally denounced all acts of violence in the name of Islam and Allah.
Speaking to Premier the Patriarch of the Syriac Orthodox Church, His Grace Ignatius Aphrem II (below), said the British government must do more to stop the persecution of Christians and other believers.
He said: "They're definitely not helping, but I cannot say they're hindering on purpose, or intentionally.
"The result of this war in Syria... is not only hindering, it is putting an end to Christianity in Syria. We have more than forty percent of Christians now who've left Syria.
"The UK and other governments have to stop this and they can do that by stopping funding, or by putting an end to funding that comes from third [party] countries in the area.
"The UK can put pressure on these countries to stop funding these terorrists, to stop getting arms and ammunition to them and to broker peace, to let Syrians sit together and work for peace for their country."
And Lord David Alton (below), who was part of the report's launch, told Premier: "We have sold more than 3.2 billion pounds of weapons to Saudi Arabia, aiding and abetting the spread of wahhabism [an extreme interpretation of Islam] around the world.
"It is crazy that we should be aiding and abetting this by either selling our technology, or allowing the flow of arms, into the hands of people who then take up arms against not just Christian minorities, but people who refuse to comply with their particular form of religious dictat.
"I remember a Sudanese bishop saying to me in South Sudan, where two million people died as attempts were made by Khartoum to impose Sharia law on the south of Sudan: 'You do realise that every barrel of oil you buy from Saudi Arabia is half full of our blood'."
A Foreign Office spokeswoman said: "Freedom of Religion or Belief is a fundamental human right that everyone should be able to enjoy. We are firmly committed to promoting and protecting it across the world and just last month held a groundbreaking conference to explore how freedom of religion of belief can help prevent violent extremism.
"We are supporting diplomatic efforts to end violence and investigate the desperate human rights situation. The UK is also providing over £2.3 billion in response to the humanitarian crisis inside Syria and neighbouring countries.
"Ultimately, our aim is to establish lasting peace in Syria through an inclusive political settlement. This is also the best way of safeguarding affected minority communities, including Christians."
And commenting on Saudi arms sales, a Foreign Office spokeswoman said: "The UK takes its arms export responsibilities very seriously and operates one of the most robust arms export control regimes in the world.
"We rigorously examine every application on a case-by-case basis against the Consolidated EU and National arms export licensing Criteria.
"We draw on all available information, including reports from NGOs and our overseas network."
Listen to Premier's Aaron James speaking to His Grace Ignatius Aphrem II:
Listen to Premier's Aaron James speaking to Lord David Alton:
