Dublin is on high alert during the Queen’s visit today after a bomb was discovered near the Irish capital and a second suspect package was found. She becomes the first British monarch to visit southern Ireland since King George V in 1911.

An explosive device was found in the luggage compartment of a bus in Maynooth, just outside the city, and was destroyed in the early hours of this morning, an army spokesman confirmed.

A second package was found at a tram station in Inchicore, Dublin, however this was found out to be a hoax.

As Ireland’s biggest-ever security operation is carried, police are patrolling the streets, and large parts of the city remain closed off over security fears.

Irish Prime Minister Enda Kenny described the threat as “minimal” and insisted that the Royal visit would be not be cancelled.

He said: “They’ve put in place a comprehensive security operation. You’ll recall we’ve had American Presidents here before, a Pope.

“So obviously while there have been incidents, the Gardai (police) have been able to deal with those.”

Yesterday parts of central London were cordoned off for eight hours after a coded bomb warning from Irish dissidents was sent to Scotland Yard, stoking fears of an attack on the British mainland.

Officials said the message, made from a telephone in the Irish Republic on Sunday night, was the first coded warning in Britain for at least ten years.

There are concerns a massive lockdown in Dublin ahead of the Queen’s arrival today could force extremists to seek ‘softer’ targets.

The city was at the centre of the biggest security operation in the Irish Republic’s history as the Queen’s four-day state visit gets under way.

More than 8,000 Irish police and 2,000 troops will be deployed in a £26million operation.

Some groups have been angered by the Queen’s itinerary which includes a wreath-laying ceremony today at Dublin’s Garden of Remembrance, which honours all those who fought for Irish freedom, and a visit to Croke Park, scene of a massacre in 1920.

The Queen is being protected by 120 armed British police officers as she becomes the first British monarch to visit southern Ireland since King George V in 1911.