Deputy event organiser Sarah Sanders says: "We've had to close off the town a little earlier than planned because all the car parks are unfortunately full."

Selected town residents, including children as young as seven, take turns to run through the streets carrying burning wooden firkins in an "ancient rite of passage," Andrew Wade, president of the Tar Barrels Committee, says.

Mr Wade says there are "lots of ideas of how it first started" but looking back through history, "most of it was to do with 1605 when bonfires and effigies were burnt and barrels were plentiful".

"I think it's more to do with the gunpowder plot than anything else," he says.

"The barrels used to be rolled, that's why the people are called barrel rollers.

"Someone probably decided I'm fed up with this, I'm going to lift one up and carry it - and there it all started."

Geoff Abbott, one of the event stewards, says it is a "surreal" feeling to roll a barrel.

"The heat and smell is something I have never experienced before," he says.

"I've been going to tar barrels since a little lad but carrying the barrel is something else."

It is a year-long task to fundraise for the event, he continues.

"Insurance alone is colossal as you might expect," he adds.

Tim Whiteoak, station manager for Devon and Somerset Fire and Rescue, says the annual event is "ironically" fairly safe.

"We’ve hardly had any incidents and certainly none relating to the tar barrels," he says.

"That is testament to the organisation of the event and the partnership with the blue light services."

Sarah Sanders, one of the organisers, says the car parks are really filling up.

She says people will be able to find space later but at the moment they are near capacity and they will have to find space elsewhere.

Darrin Abbott, who was born and bred in Ottery St Mary, has travelled from Hawaii to take part in the event.

"This is our Christmas... I wouldn't miss this for the world," he says.

The local library is being used as a safety base at the event.

Supt Int Joe Matthews said police were working with the council, fire and the ambulance service to keep people "as safe as possible".

Director Ash Franks says the event uses St Johns Ambulance Service on board as well as its own medical services.

Darrin Abbott, one of the veterans of the event, says "everything is absolutely controlled".

"One this finishes we'll have a debrief and take a cold hard look at what we've done and what worked well," he says.

Organisers say the historic event is believed to have started after the Gunpowder Plot of 1605, when a group of English Catholics attempted to kill King James VI.

Andrew Wade, president of the Tar Barrels committee, says there are "lots of ideas of how it first started" but looking back through history, "most of it was to do with 1605 when bonfires and effigies were burnt and barrels were plentiful".

"I think it's more to do with the Gunpowder Plot than anything else," he adds.

Our live stream from the Ottery St Mary Tar Barrels has started.

Soak up all the excitement with BBC Spotlight's Victoria Graham and Erin Black by clicking the live feed above or heading over to iPlayer.

Cameron Weldon
in Ottery St Mary

The party is really getting started here in Ottery St Mary.

This is a rite of passage for local people, especially the younger generation, as they have all seen their family members all taking part previously.

The barrels are pretty heavy and the fact they are on fire makes it significantly harder to carry.

They are only getting heavier as the evening goes on - some of them are absolutely huge.

I don't envy anyone having to pick one of those up.

You may be wondering how people keep themselves safe from the flaming tar barrels being carried above their heads.

The only piece of "specialist" clothing worn for the event are gloves made of heavy sacking.

Andrew Wade, president of the Tar Barrels Committee, says participants sometimes strapped their arms up and may put petroleum jelly on their face.

He also says people tend to wear the same thing every year.

Join BBC Spotlight's Victoria Graham and Erin Black from 19:00 GMT in Ottery St Mary.

We'll be bringing you a live stream of the event on BBC iPlayer as well as right here on this page.

Hattie McCann
in Ottery St Mary

It's an absolute hive of activity, there's excitement everywhere and there's the barrels - they are on fire out of both ends.

People are laughing, chatting and dodging out of the way of the barrels.

There's one coming towards me right now and someone has added some extra juice to it to make the flames nice and big.

It's just doing laps of the main square and everyone is just enjoying it.

Cameron Weldon
in Ottery St Mary

It's absolutely incredible - a sight to behold.

Young lads with rugby tops on are just grabbing these barrels - all they've got is their hessian gloves on and they're just charging around the town square.

Some of them are running a fair distance with the barrels before putting it down again.

This is a very heavy barrel covered in flames. It is an absolute spectacle.

• There are 11 children's barrels, at regular intervals until the final one at 18:15
• At 18:30 the bonfire will be lit in St Saviour's meadow
• The women's, men's and intermediate barrels begin at 19:00
• There will be 16 barrels through the evening, at regular intervals until the final one, the Midnight Barrel departs from The Square at 23:59

Erin Black
in Ottery St Mary

There are groups of people, locals and visitors alike, streaming in to Ottery St Mary.

It's just started spitting rain but people aren't letting that dampen their spirits.

I was speaking to one of the barrel rollers earlier and he said the weather is irrelevant - they'll go through with it whatever happens.