According to The Times, the British independent inquiry into child sexual abuse was told that the Vatican deemed the requests to be inappropriate.
It's been reported that Jacqueline Carey, counsel to the inquiry, told a preliminary hearing that the Vatican had been asked to give written evidence about sexual abuse cases in Britain and provide a senior official to present the evidence.
Carey said: "The Holy See confirmed that it would not be providing a witness statement or a witness to attend the hearing. The Holy See considers that the 'domestic laws and internal proceedings of a foreign sovereign entity are not the proper object for a British inquiry'."
She added that the Vatican said Archbishop Edward Adams, the papal nuncio to Britain, had diplomatic immunity and could not be forced to testify.
The inquiry has investigated behaviour by some priests in Ealing Abbey in west London, and in the diocese of Birmingham.
Gabrielle Shaw from the National Association for People Abused in Childhood, told The Times: "This is a really disappointing missed opportunity for the Vatican to show its commitment to Catholic survivors in the UK.
"The Vatican has a real chance here to set an example for all faiths by working with and supporting survivors across borders."
Pope Francis has recently spoken out against sexual abuse in the Catholic Church. In February the Vatican held a summit on how to deal with cases of sex abuse by clergy.
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