London festival and parade: St Patrick's Day was marked early in London, as some 30,000 people answered the organisers' call to celebrate "all things Irish".
A parade and a festival designed to promote Ireland, turned parts of the city green with flags, bunting and memorabilia.
Celebrities including Cold Feet star, James Nesbitt, and former Irish football manager, Mick McCarthy, also turned out to support the event, now in its second year.
In blazing sunshine and overlooked by the London Eye, the revellers cheered on Irish musical acts performing on a large stage in Jubilee Gardens.
The London Mayor, Mr Ken Livingstone, whose office helped organise the event, thanked the crowds for supporting the day.
He said there were "a lot of people living in London with not a drop of Irish blood in them," but they still felt able to join in with the celebrations.
Later today Mr Livingstone was due to sign a Friendship Agreement between London and Dublin to build up the economic, social and cultural links between the two cities.
Ms Judith Woodward, who organiseed the celebrations on behalf of the Mayor, said: "We've had tens of thousands of Londoners participating in the second official St Patrick's Day parade, watching the parade and lining the route through central London.
"It's been an absolutely fantastic day. It's been safe, good-humoured and we've all enjoyed the wonderful Irish craic. In some ways the highlight has been the weather, which couldn't have been better.
"The parade has been going from strength to strength. Last year Mayor Livingstone said he wanted to create a parade that would rival those in New York and Dublin. That's going to take time, and we're not there yet."
She added that visitors watching the parade saw eight marching bands, 15 floats, numerous dancing schools and troupes representing Irish county associations and other community organisations.
About 10,000 people took part in the parade and about 50,000 people visited the various Irish stalls lining the South Bank or listened to performers, at any one time.
Marquees along the Queen's Walk area showcased Irish food and drink, arts and crafts, music and dance.