The Pope’s letter has been criticised for not adequately addressing the issues of accountability for abuse or for the cover up of crimes.

Survivor Colm O’Gorman said the Pope has still not admitted to the “deliberate policy of cover up, designed and implemented by the Vatican”.

“He seeks forgiveness for our pain and named the need to root out abuse and cover-up, all welcome. But he once again fails to name who is responsible for the cover-up,” Mr O’Gorman said in a series of tweets shortly after the publication of the letter on Monday.

The former head of the One in Four charity said while Pope Francis had said the church must seek forgiveness for its sins, he did not acknowledge its “wilful cover up of those very crimes”.

“He names the clerical culture that was a major factor in all of this and how Church leaders were more concerned with their reputation than protecting children. All true. But that culture was overseen by #Vatican & codified into its laws,” he said.

Mr O’Gorman did acknowledge that the letter “goes further” than previous church efforts to address the abuse scandal and had adopted stronger language.

“But it is wearying to have to constantly respond to such communications, to have to point out that they avoid making a simple, frank & truthful acknowledgement of the #Vatican led cover up. Just tell the damn truth.”

The Dublin abuse survivor Marie Collins also responded to the communiqué via social media, demanding the Pope address the issue of accountability.

“Statements from Vatican or Pope should stop telling us how terrible abuse is and how all must be held accountable,” she said. “Tell us instead what you are doing to hold them accountable. That is what we want to hear. ‘Working on it’ is not an acceptable explanation for decades of ‘delay’.”

Last year, Ms Collins resigned from the Commission for the Protection of Minors in protest at the frustration of its work by Vatican officials.

She noted the letter lacked any “plan of action” and said actions should be taken to ensure abusers were no longer protected by the church.

One in Four meanwhile issued a statement saying it was disappointed and frustrated by the Pope’s message.

It said the letter was a “rehashing” of apologies without any substantive explanation as to how it planned to address the issue of accountability for both crime and cover-up.

“There is nothing in this new communication from Pope Francis to show that the Vatican intends to put in place clear laws and protocols that will hold every bishop and cardinal who shield sex offenders and place them in positions where they can continue to abuse children,” said its executive director Maeve Lewis. “Survivors are tired of meaningless apologies and expressions of solidarity that do not involve a clear call to action.”

She said that while investigations have been conducted into child sex abuse in countries with robust criminal justice systems, she was “appalled to think of what must be happening in the developing world, where millions of Catholic children live, and where priests and the hierarchy are still treated as an untouchable elite”.

One in Four has called on Pope Francis to establish a system of mandatory reporting to civil authorities across the world.

“The Pope’s visit is very distressing to many survivors, retriggering old emotions of shame, humiliation, despair and anger,” Ms Lewis said.

“The least they deserve during this papal visit is a clear commitment that the Catholic Church finally intends to deal with clerical child sexual abuse.”