A visit by the Duchess of Abercorn to Pomeroy primary school yesterday was postponed at the 11th hour after moves to block it by Sinn Fein.
The duchess had been due to visit St Mary's primary school in the nationalist Tyrone village to promote the Pushkin awards scheme - a literary competition for schoolchildren.
However, news of her visit reached Sinn Fein at the weekend and one councillor demanded that the invitation be withdrawn.
Mr Finbar Conway said parents had not been made aware of the visit to the Catholic primary school.
"This invitation was issued without consulting parents. People were very annoyed and felt it should not take place. In reality, it is a royal visit dressed up as a package and presented as an exercise to do with the Pushkin award." He hoped yesterday's cancellation of the visit would be the finish of it.
"I hope it does not rear its ugly head again. This is a nationalist school. The royal family has a record of open discrimination towards Catholics, and St Mary's is a Catholic school."
However, the Duchess of Abercorn pointed out that she was not a member of the British royal family, but a descendant of the Russian poet, Alexander Pushkin.
She said the school's principal, Mr Michael Harvey, had found himself in a difficult situation. "It is something which should be sorted out within the community and the school itself."
The Minister for Education, Sinn Fein's Mr Martin McGuinness, said who visited a particular school was a matter for the school principal and the chairman of the board of governors. Where there was disagreement he would hope "that it would be settled amicably between the people here directly involved."
He said he had spoken to the school's principal and was hopeful the matter could be resolved satisfactorily.
Mr Tom McKee of the teaching union NASUWT, said: "It is intolerable that a political party should arrogate to itself the right to ensure who visits schools. First, it was the RUC, now the Duchess of Abercorn. Who else is on the Sinn Fein exclusion list?"
Criticism came from across the political divide, with accusations of bigotry and sectarianism being levelled at Sinn Fein.
Mr Denis Haughey, the SDLP Assembly member for mid-Ulster, questioned the "growing level of intimidation, by overt or other means" by Sinn Fein. He cited the recent controversy in Carrickmore, where attempts were made to oust Mgr Denis Faul as parish priest after he had meetings with the RUC.