Is this a charge to pray? An enforced donation towards upkeep? Or a user-pays fee, similar to charges applied by museums and art galleries?
The first such fees began to appear a decade or so ago, on a small and modest scale, but are now quite common - and several times higher than before.
And the storm they stirred won't still. Some critics say an entrance fee destroys individual worship and contemplation. Others even liken entry-chargers to the avaricious money-lenders that Jesus cast from the Temple.
The controversy has been stirred anew by a veteran religious writer, William Oddie, who issued a call for visitors to refuse to pay to enter York Minster.
"This is the house of God: and to charge money for entrance to it is tantamount to simony, one definition of which is 'trafficking for money in spiritual things'," Oddie wrote in the weekly British newspaper the Catholic Herald in July.
More than 150 people wrote to the paper in response, many of them echoing his outrage.
Churches who charge the fees say that those seeking genuinely to pray rather than sightsee can come in for free. But one Anglican priest said that he had had a nightmare in trying to invoke this right: "It was even suggested I was pretending to be a priest to get in."
Oddie told the Herald he wasn't surprised by the sharp reaction: "There's quite a lot of strong feeling on this subject."
The churches themselves say they only introduced the fees after voluntary donations failed to work.
"We rely on the income generated by tourism to allow the building to continue to function as a centre for Christian worship, as well as to cover general maintenance and repair work," Hannah Talbot of St Paul's said by email.
York Minster says it needs at least £20,000 a day for maintenance and, even though it lures millions of tourists to the city each year, it receives not a penny in state subsidy. Added to that is its intangible value as an artistic resource.
In continental Europe, places of worship are almost invariably free of charge.
"We spent a wonderfully peaceful half hour in Notre-Dame," an American woman who lives in London said of a Paris visit with her 83-year-old mother.
"We simply sat and listened to the singing by the choir. I doubt we would have paid to enter."