Thousands lined the streets of Dublin today to enjoy a host of St Patrick’s Day festivities.

Buoyant revellers from across the globe crammed the city's streets for the two-hour spectacle, which saw street theatre troupes, pageantry, dancers and marching bands weave the 3km route.

Some 3,000 performers took part in the parade which was one of the highlights of the five-day St Patrick's Festival.

An estimated half a million people turned out for the parade, said St Patrick's Festival chief executive Susan Kirby.

"We were very, very pleased with it," Ms Kirby said. "I think Dublin and its people looked very well. I would hope that if even for a short while we were putting our best foot forward and demonstrating what an optimistic country we are."

For the first time a short story was the inspiration behind the parade, with Brilliant by Roddy Doyle chosen for the honour because of Dublin's designation as a Unesco City of Literature.

It tells the story of two children and the quest to banish the black dog of depression over the city - a reference to the financial woes of the last year.

Leading pageant companies including City Fusion, Brighter Futures, LUXe, Macnas, Artastic, Inishowen, Spraoi and Bui Bolg interpreted different chapters of the story.

Mr Doyle said he penned the piece while watching news reels of the International Monetary Fund arriving in Dublin last November. "It was a reaction to that really, that's why I wrote the story," he said.

President Mary McAleese joined other dignitaries on the VIP seats by the General Post Office on O'Connell Street, including Dublin Lord Mayor Gerry Breen who arrived in a restored gilded horse-drawn carriage.