The Special Criminal Court also found the man guilty of making a number of hoax bomb threats
A man has been found guilty of possessing an explosive device at Longford railway station during the 2011 visit of Queen Elizabeth to Ireland.
Donal Billings of St. Bridget’s Court in Drumlish, Co. Longford was also convicted of making hoax bomb threats during her trip.
A trial at the Special Criminal Court heard that the day before Queen Elizabeth’s arrival in Ireland, Gardaí received a call warning that a bomb had been planted on the Ballina to Dublin bus.
The caller also claimed that there were explosive devices at Busáras and Sinn Féin headquarters.
A bomb with a firework as a detonator and some flammable liquid was found on the bus, but no other devices were recovered.
A second call claiming two mortars were set to target Dublin castle - where the Queen was attending a state function - was made two days later.
A third call claiming there were two bombs at Cork airport was made the day she was due to fly out of the city.
Mr. Justice Tony Hunt said he and his fellow judges at the non-jury Special Criminal Court were satisfied that Mr Billings had made the calls and placed the improvised device on the bus at Longford railway station.
The 65-year-old was remanded in custody with a sentencing hearing due for the end of next month.