Rows over gay marriage and women bishops bewilder most people. With overwhelming popular support for both, how can abstruse theology and unpleasant prejudice cause such agitation at Westminster and in the rightwing press? Politics looks even more out of touch when obscure doctrine holds a disproportionate place in national life.

The religions still frighten politicians, because despite small numbers in the pews, synagogues and mosques, they are organised and vocal when most of the rest of society lacks community voice or influence. Labour was craven, endlessly wooing faith groups – David Blunkett wishing he could "bottle the magic" of faith schools.

With a third of state schools religious in this most secular country, Michael Gove not only swells their number but lets them discriminate as they please in admissions. As he is sending a bible to every English school, the BHA is fundraising to send out its own Young Atheist's Handbook to school libraries. Government departments are outsourcing more services to faith groups in health, hospice, community and social care.

But of all the battles Jim Al-Khalili confronts, the most urgent is the right to die. Powerful religious forces block attempts to let the dying end their lives when they choose. Tony Nicklinson was the most public face of thousands in care homes and hospitals condemned to what he called "a living nightmare" by 26 bishops and other religious lords who say only God can dispose – the Bishop of Oxford decreed: "We are not autonomous beings." The public supports the right to die, but many more will drag themselves off to a bleak Swiss clinic before the religions let us die in peace.

Sensing the ebbing tide of faith since the last census, the blowback against unbelievers has been remarkably violently expressed. Puzzlingly, we are routinely referred to as "aggressive atheists" as if non-belief itself were an affront. But we are with Voltaire, defending to the death people's right to believe whatever they choose, but fighting to prevent them imposing their creeds on others.