By politics.co.uk staff
The Queen has continued with her historic visit to Ireland despite the discovery of bomb on a bus bound for Dublin.
Amid an unprecedented security operation, the Queen met president Mary McAleese and taoiseach Enda Kenny at Aras an Uachtarain, in Dublin.
In a visit heavy on symbolism, the Queen emerged from Baldonnel military airbase wearing a green coat and hat.
The Irish and Union flags flew next to each other as a 21-gun salute marked her arrival.
In a moment which would have been unthinkable even two decades ago, God Save the Queen was played by Irish guards.
The calm and businesslike continuation of the trip continued despite the attempts by nationalist extremists to disrupt proceedings.
Thirty people were on a bus heading to Dublin overnight when a "viable improvised explosive device" was discovered.
They were transferred to another vehicle while the device was detonated in a controlled explosion.
Thousands of manhole covers and lamp posts are being checked by a 4,000-strong team in Ireland, while separate bomb threats in London have also prompted a major police operation.
But the warnings are unlikely to upset the historic visit, which sees the Queen become the first reigning monarch to visit the country since 1911.
"One hundred years on from the last time a British monarch visited Ireland, I think there is a great sense of history and occasion," David Cameron said.
"I think the real effect will be a marker that just as we are solving some of the problems there have been between us in the past, just as we are helping each other through these difficult economic times, now is a great moment for people in Britain and people in Ireland to remember what it is we share."
The Queen will visit president attend events in Trinity College Dublin and the National War Memorial Gardens in Islandbridge.