It probably wasn’t what the Pope was expecting from his Vatican gathering on Monday – a lesson on the importance of sex in a relationship.

Australian couple, Ron and Mavis Pirola, were asked to talk about what makes a marriage last.

In front of 200 prelates, they gamely explained that sex is crucial for a successful relationship.

They have been married for 55 years.

“The little things we did for each other, the telephone calls and love notes, the way we planned our day around each other and the things we shared were outward expressions of our longing to be intimate with each other,” the couple said in a joint statement.

“Gradually we came to see that the only feature that distinguishes our sacramental relationship from that of any other good Christ-centred relationship is sexual intimacy, and that marriage is a sexual sacrament with its fullest expression in sexual intercourse.”

The congregation of celibate men were a little bemused by the admission.

“That’s not what we bishops talk about mostly, quite honestly,” a sheepish British cardinal, Vincent Nichols, told reporters on Tuesday. “But to hear that as the opening contribution did, I think, open an area... and it was a recognition that that is central to the well-being of marriage often.”

The meeting was organised by the Pope to work out how to make Catholic teaching on issues such as marriage, divorce, homosexuality and sex more relevant to the church today.

The Pirolas’ told a story of how their Catholic friends were happy to invite their gay son’s partner to a Christmas gathering.