Thousands gather in towns and cities for St Patrick's Day celebrations

Thousands of people, many of them dressed in green, have gathered in towns and cities across Northern Ireland to celebrate St Patrick's Day.

It is a national holiday in Northern Ireland and the Republic of Ireland, with parades and parties taking place to mark the day.

Belfast's annual paradeis weaving its way through the city centre, with a colourful live performance.

In Dublin, the largest parade on the island has begun, featuring 12 large-scale floats with more than 3,000 participants.

Thousands of people are lining the streets of Belfast, grateful there has been no rain to dampen their St Patrick's Day celebrations.

The sun even peeped out as the parade left the grounds of city hall.

The floats, dancers and musicians are snaking their way through the city centre before returning to the city hall.

This is one of the biggest parades on the island and a definite highlight in the city hall's cultural timetable.

It's not the only way the city marks the day - thousands of runners were out for the Spar Craic 10k earlier on Tuesday.

Outside St Anne's Cathedral there was a ceili and food village welcoming families and there will be a special concert at the MAC theatre.

The lord mayor of Belfast said there was a "good festival atmosphere".

"Belfast works hard to deliver to all cultures all year," said Tracey Kelly.

"It's a bit strange for me this year. I'm usually watching the parade so actually leading the parade as the lord mayor will be a bit surreal."

In Downpatrick, home of the final resting place of the saint himself, thousands took to the streets for the annual parade.

A sea of green, painted faces and leprechaun hats - the crowds cheered on as dance troupes, brass bands and pipers snaked through the town.

Leo travelled from Banbridge with his family to join in the fun.

He said he had been learning about St Patrick at school and knew "he didn't really chase the snakes from Ireland - it's just a myth".

Macartan Digney, from Downpatrick, said he attended the festivities every year.

"This is both a celebration of St Patrick - and our town as well," he told BBC News NI.

At Down Cathedral, a more sombre religious celebration with the annual wreath laying service at St Patrick's grave took place on Tuesday morning.

Tens of thousands of people are expected in the centre of Derry for a programme of music, dance, food and folklore.

The city's spring carnival parade will start to make its way through the town centre at 15:00 GMT.

Katie Lyttle and Ethan Hegarty were enjoying the music in Guildhall Square despite the rain.

"I love it. It's the best place to come. The music is really good," said Katie.

Ethan said it was "amazing and good craic."

Mayor Ruairí McHugh said it had been a long winter but "with colour returning to our green spaces and brighter weather and longer evenings there is a genuine feeling of excitement building".

He said the parade "gets bigger and better" every year.

Thousands of people are in Enniskillen to celebrate St Patrick's Day.

The mini festival started on Monday night with 40 boats taking part in a flotilla on Lough Erne.

St Patrick arrived in the island town by boat and was joined by two Irish wolfhounds as he made his way around Enniskillen castle.

The mini festival is themed "shamrocks and shared stories", and elaborate sculptures celebrating Irish history and stories will take part in a parade through the town.

Irish TV presenter Vogue Williams is leading the parade in Dublin, which kicked off at 12:00 local time.

Up to half a million people are lining the streets there. The theme this year is "roots", to celebrate the people, places and stories of Ireland.

Saint Patrick is the patron saint of Ireland, he lived in the 5th century AD and is understood to have played a major part in converting the Irish to Christianity.

While St Patrick really existed, and some of his writings survive, his value does not really come from historical details but from the inspiration of a man who returned to the country where he had been a child slave, in order to bring the message of Christ.

He is traditionally associated with the shamrock plant, which he used to explain the Christian doctrine of the Holy Trinity.

Additional reporting by Keiron Tourish, Eve Rosato, Elaine Mitchell and Lyndsey Telford.