Fine Gael MEP for Dublin Gay Mitchell described it as a “churlish decision to ban an innocuous advertisement” while independent Senator Ronan Mullins said it was “deeply insulting” to religious people in Ireland.

“This is really rubbing the noses of Christian organisations” said Mr Mitchell.

“There is no other group in Ireland which would have this exacting interpretation applied to it. It would be laughed at in Europe and would not stand up to a challenge in the European Court of Human Rights.

“The Broadcasting Authority should be called before an Oireachtas Committee and asked to explain how their supposed balanced policies can be so arbitrarily applied to a Christian bookshop at Christmas time.”

Senator Rónán Mullen said the ban was deeply insulting to people of faith and illustrated a “values vacuum” in high places and that only a commercialised version of Christmas seemed to be acceptable to some.

“It appears that you can legally advertise any service or product however useless or tangential in its connection to Christmas, but the very Christianity that gives meaning to Christmas does not get a look-in.

“If you carry the logic of the BCI to its logical conclusion then all adverts mentioning Christmas should be banned, because, like it or not, Christmas is a religious festival and always has been.”

Mr Mullen called on the Minister for Communications to overturn the ban in the Broadcasting Bill which is still before the Dáil. He also wondered how well the ban sat with the pledge by the State in article 44 of the Constitution to “respect and honour religion”.

“There may be case law to suggest that the BCI may not be violating the Constitution, but its actions look very bad when viewed alongside the requirement that the State ‘shall not impose any disabilities or make any discrimination on the ground of religious profession, belief or status’.”