The British taxpayer is helping alleviate suffering in four out of five of the countries listed as where Christians are most persecuted.
Of the 50 nations where it is most difficult to live as a Christian, Britain gave aid to 40.
An analysis by the Telegraph of international aid compared with the Open Doors World Watch List shows that countries where living the gospel means imprisonment, discrimination and abuse received nearly £2.4 billion from the Department for International Development, with nearly another £320 million from official agencies.
Christians in the Middle East and parts of Africa are facing repeated attacks from terrorist extremists and there are growing fears that the faith could be wiped out completely in some of those countries where it first began. Prime Minister David Cameron said recently that Christianity is now the most persecuted religion around the world and Britain should be unashamed to stand up for religious freedom.
The rise of Islamic extremism accounts for 40 of the 50 entries on the Open Doors watch list.
Somalia, which ranks second to North Korea for persecution of Christians, received £107.3 million in aid from the UK. Iraq, where Christians have suffered unprecedented losses at the hands of Islamic State, received £7 million.
Pakistan, where Christians are suffering under harsh blasphemy laws, received almost £34 million.
Bishop Michael Nazir-Ali, the former Bishop of Rochester who is now president of Oxtrad, a charity supporting churches facing persecution, told the Telegraph: "Britain's commitment to aid is praiseworthy but we must make sure that it is directed properly to the right people in the right way.
"I think we have to target it very carefully and where there is real need to make sure that aid is not being used simply to support British business or other interests and certainly to make sure that it is not being used to sustain corruption."
A DFID spokesman said: "British aid is tackling discrimination head on – to suggest otherwise is deeply misleading. DFID is working closely with our charity partners to help create more open and free societies.
"The truth is, stopping aid to these countries is counterproductive.
"It will simply cut support to persecuted men, women and children, and harm the future health, education and welfare of the world's poorest people."