The Rev. James MacKay said he was leading the Eucharistic prayer July 1 at the Cathedral Church of St. Mary and St. Helen in Brentwood, England, when he heard a sound like an "explosion," the BBC reported Monday.
"Everything stopped as we heard this. I turned to my left to see lots of slate and what looked like white stuff, which we now know was ice, falling from the roof," MacKay said. "I was trembling with a bit of shock. After a couple of seconds of shocked pause I said 'right, let's crack on' and we did so."
The Civil Aviation Authority said there are about 30 reports of ice falling from aircraft each year.
"Ice falling from planes does not happen that often -- it can happen around hose connections and if washers fail," a CAA spokesman said. "You can have a big lump of ice come off an aircraft as it descends into warmer air."
MacKay said the damage to the roof and beams of the cathedral, which was finished in 1991, cost hundreds of dollars to repair.