Mervyn Thomas was a founder of CSW, a Christian advocacy organisation campaigning for Freedom of Religion or Belief (FoRB), in 1979. 

He chaired the Board until 1999, before being appointed Chief Executive, a position he held until moving into the role of Founder President in September 2020. 

In addition to his work with CSW, Mervyn chairs the UK FoRB Forum and works closely with the UK Prime Minister’s Special Envoy for FoRB, the UK All Party Parliamentary Group on FoRB, and the International Panel of Parliamentarians for FoRB. 

He was founder Chairman of the Religious Liberty Partnership (RLP) - an international network of around 70 Christian organisations working for FoRB, from over 25 countries – and was its Chair from 2006 until he stood down in 2019. 

Between 2010-2024 he advised British Foreign Secretaries on FoRB issues, as a member of their Human Rights Advisory Group, and worked particularly closely with the Bishop of Truro on his Independent Review into UK Government support for persecuted Christians. 

He has regularly testified in both the UK and European Parliaments, at Congressional Hearings on Capitol Hill and at the United Nations. He was also a plenary speaker at the FoRB Ministerial Conference in London in 2022. 

Mervyn is an ordained Assemblies of God Minister and a member of the World Pentecostal Churches Commission on Religious Liberty. 

For the past forty seven years Mervyn has traveled widely to countries where religious minorities suffer persecution because of their faith or belief, and is an internationally known, inspirational speaker on behalf of persecuted minorities. 

In 2019 Mervyn was appointed a Companion of the Most Distinguished Order of St Michael and St George (CMG) by HM Queen Elizabeth II, for services to Human Rights and Freedom of Religion or Belief.