The scientific part of the process, which is seen as the most complicated, has already been completed, with just the theological part incomplete, said deputy postulator Ângela Coelho, who believes that news could emerge when the pontiff is in Portugal on 12 and 13 May.

“There is ever more hope that there is canonisation [of Francisco and Jacinta Marto] during 2017," Coelho told Lusa. "As to the time and place of the announcement, as well as the place and date of the canonisation, that will depend on the Pope."

She stressed, however, that at present things are still "in the world of expectations and not certainties".

On 13 May of 2000, Pope John Paul II beatified the two long-dead children while he himself was on a visit to Fátima. There followed a long process that could lead to their canonisation, and which was at one point delayed because of problems in validating an alleged miracle.

In the meantime a new "grace" emerged in Brazil in 2013 that was approved by Church medical doctors, who pronounced that the child in question had been cured of an illness with no scientific explanation; the theologians must now pronounce that this happened "in the context of faith and of evocation of the Blessed Francisco and Jacinta and only of these Blessed."

Now that the process is in the final stretch, Coelho said she was "very expectant" and that she believed the pope will take into account the symbolism of the centenary of the "apparitions" on 13 May, when he will be with thousands of pilgrims in Fátima.

"I believe that he may also want to give the pilgrims joy," she said.

The process began in 1981, with the alteration of ecclesiastical rules to allow children to be canonised. After their beatification, the process of canonisation was begun in 2004. If they become saints, they will be the youngest ever.