WHOSE calculations, FW - yours? Lets see the EVIDENCE for this preposterous claim.

Not mine Greg. That was a quote from yesterday's Times.
Here are a few more people who make the "preposterous claim" (taken from Jim's link)
"In a rare theological intervention at a Downing Street reception yesterday, David Cameron made the eye-catching suggestion that Christians were the most persecuted religious group in the world today.
The PM is not the first prominent figure to make such a claim. Pope Benedict XVI said it during his New Year message in 2011, Angela Merkel made similar remarks during a visit to a church in November 2012, and late last year Prince Charles spoke of "intimidation, false accusation and organised persecution to the Christian communities in the Middle East at the present time."

Tragic news reports seem to bear this out. The destruction of ancient Christian communities in their homelands in Iraq, Syria and other parts of the Middle East, described by Tom Holland as "a crime against civilisation as well as against humanity", has been one of the most depressing consequences of the recent turmoil. Sometimes, direct religious persecution seems to be involved, as in this week's murder of Dutch priest Frans van der Lugt in the besieged town of Homs. Meanwhile, in Pakistan yet another absurd blasphemy prosecution came to light, this time of a Christian couple sentenced to death (and a fine!) for allegedly sending text messages deemed to be offensive to Islam.

And let's not forget North Korea, officially the worst country in the world to be a Christian, where a few weeks ago 33 Baptist missionaries are said to have been sentenced to death on the personal orders of Kim Jong-Un.

The persecution of Christians has been the subject of some recent books. The US Catholic journalist John Allen entitled his The Global War on Christians, maintaining that Christians as a whole were "indisputably ... the most persecuted religious body on the planet". Writing in the Spectator, Allen commented that,

the world is witnessing the rise of an entire new generation of Christian martyrs. The carnage is occurring on such a vast scale that it represents not only the most dramatic Christian story of our time, but arguably the premier human rights challenge of this era as well."

In slightly less apocalyptic vein, British author Rupert Shortt in his recent book Christianophobia: A faith under attack catalogues violent targeting of Christians from Nigeria to the far east as well as less lethal but clear human rights abuses and intimidation. In an interview with Alan Johnson, Shortt said that "in a vast belt of land from Morocco to Pakistan there is scarcely a single country in which Christians can worship entirely without harassment".

"Rather more rigorous data has been assembled by the Pew Research Forum in a report produced earlier this year. Pew found that official "restriction on religion" (a more objective term than "persecution") was at the highest level for six years, as was the "social harassment" of members of religious communities. And Christians, indeed, were the most affected group. Christians faced harassment in no fewer than 151 countries worldwide – and not just in the Middle East, China or North Korea."