Beyond the hustle and bustle of Cabot Circus, with its shoppers and roads roaring with traffic, the streets of St Paul's shook to a different sound on Saturday – carnival time.

Portland Square was filled with the noise of thumping drums, shrill whistles and samba beats, and an enormous procession of dancers, bands and colourful costumes set off on Saturday afternoon.

The 42nd St Paul's Carnival, a celebration of Afro-Caribbean arts and culture in Bristol, was well and truly underway.

Leading the procession was 11-year-old Karmell Allman, who lives in St Paul's.

The youngster wore a huge green and blue costume shaped like a fan, with green feathers, gold tassels and the slogan "leaders of tomorrow", this year's carnival theme.

Karmell said: "I am really excited about it but am a little scared. It is the first time I have every done it, so I am quite nervous."

Behind him were 15 children from Cabot Primary School and their teachers, the first of about 30 groups that made up the parade.

The pupils were dressed in red, blue and green costumes to represent fire, nature and the sea and they danced to Shoka music.

Courtney Moffett, 10, said: "We are global warming, and we are the scientists of the future as we are going to look after the environment."

Pat Usherwood, who organised the school's involvement, said: "The children have been rehearsing for eight weeks and have been looking forward to this for a long time."

As the procession snaked its way around Portland Square, along Brigstocke Road, down Ashley Road and back along City Road, thousands of people cheered them on.

The schools led the way, 14 in total.

Youngsters from Fairfield High School, their faces painted yellow and blue, were followed by children from Glenfrome Primary, waving streamers.

Pupils from Christ Church Primary danced in amazing fire-red costumes with flame headdresses and sparkly red and gold shoes, children from St Barnabas Primary wore blue wings and masks as birds of the future, and youngsters from St Nicholas of Tolentine Primary wore gold and purple outfits holding a banner that read "considerate".

Then there were colourful stilt walkers, the Sax Pistols, Ilu Axe samba band, steel bands and Afrikan Sambistas.

Others were dressed in enormous Chinese costumes that filled the width of the street, Spanish outfits to represent spirits, flamenco outfits and bikes decorated as fish and sea creatures.

Most groups were local, but others had travelled from places like Nottingham, London and Luton.

As those in the parade danced away, onlookers took pity and squirted them with water to keep them cool in the heat – a change from last year's rain-drenched carnival.

Among those relaxing in the sun was James McGuinness, 32, a record label manager from Redcliffe Hill, with his daughter Kira, four.

James said: "The carnival is great this year. I thought the procession was brilliant and the school kids were amazing.

"The costumes were stunning and the atmosphere was really good."

Kira said: "I really like it. It has good, fun things and lots of nice colours."

But the St Paul's Carnival is not just for the young.

Sitting on a bench in Portland Square were Roma Tomkins, 87, and her friends Joyce Morris, 83, and Joyce Burns, 81, all from Bath.

Ms Tomkins said: "We have been coming here for years.

"Everybody is so friendly and busy enjoying themselves. With all the troubles going on in the world it is lovely to come to a place like this and see everyone having a good time."

In St Paul's Park poet Lawrence Hoo led a poetry corner, and in St Agnes Park was Mandela Highway, an area where children enjoyed Afrikan drumming, dance, face painting and bouncy castles.

Further into the streets of St Paul's the carnival took on a different atmosphere.

On every corner there were huge sound systems and DJs, including Negus Melody, Ghetto Force, Excalibur Sound and Ujima Sound System.

Residents sat out on their porches chatting as thousands of people crammed into Grosvenor Road and the adjacent roads.

Others opened up their gardens and set up stalls to sell drinks, pineapples and mangoes, and the rich aromas of curried goat and jerk chicken filled the air.

On the main stage at Grosvenor Green there were plenty of acts to keep people happy until the small hours of Sunday morning, including Tough Touch, Funkesteins, Planetman and reggae ambassador Earl 16 and his band The Soothsayers.

The St Paul's Carnival saw more than 65,000 visitors in 2008, and there were similar numbers this year.

But Milton Campbell, 45, a driver from St Paul's, said: "It is not as big as it was in the years before.

"I have been coming since I was a child and it is getting smaller and they are pushing it out of St Paul's.

"I want it to be actually in St Paul's, but it is getting pushed out into Portland Square too much – they are taking it away from the streets of St Paul's.

"Apart from that it is lightning, and the power of the carnival is still there."