Every July, the town of Pamplona, in the Basque region of Spain, hosts the jubilant yet terrifying Fiesta de San Fermín, where thousands of people wearing white trousers and shirts, and red sashes and neckerchiefs, fill the streets for nine days of taxing partying.

The festival’s main event, the encierro or running of the bulls, is thought to have had its beginnings in the late 13th century when bulls were moved from the countryside to the town’s public arena for bullfights.

Love or loathe the attention brought to the town, locals can thank Ernest Hemingway and his 1926 novel, The Sun Also Rises, for making the fiesta so well known.

The big build-up

Upon arriving in Pamplona, scour the many stalls for your traditional Basque outfit and be sure to buy yourself a leather wine bladder – a saviour when it comes to carting litres of sangria around at the opening ceremony.

Then, once you’ve donned your red and whites, throw on a pair of covered shoes, fill your bladder (the leather one) and head for the Plaza Consistorial, where seemingly four times the people physically capable of fitting into the space are crammed.

Keen to distinguish themselves from other Spaniards, hordes of young Basque locals with their home-cut mullet hairdos and chunky piercings spill from every balcony, window and statue.

Their green, white and red Basque flags wave proudly from the balconies as the revellers hold their neckerchiefs above their heads in full chant: “San Fer-min! San Fer-min!”

As noon strikes, the mayor fires a rocket and the celebrations heave into action with sangria, kalimotxo (a mixture of wine and cola) and champagne spraying in every direction, turning our new whites into soaked pink party get-up.

For a moment of brief reprieve, we duck under one of the giant Basque flags being passed above the crowd and pretend to sing along in Spanish, before meandering into the surrounding streets.

The music, dancing and drinking hammers on well into the night before a massive fireworks display reminds you it’s only nine hours until the main event begins.

On your marks, get set, go

The first cannon sounds at 8am and a burst of adrenaline hits. Seconds later, another cannon reverberates down the narrow windy streets, a sign all the bulls have left the corral.

The crowd sets off and before long the combination of cobblestones and too many people causes chaos.

Unable to spot the stocky black beasts tearing through the crowd I jog forward until the sea of sangria-stained runners around me gathers pace and becomes a scrambling mess, each fighting for an inch of refuge along the walls.

The first of the irate beasts thunder past within metres, thankfully none deciding to veer to their right.

To end up in the arena from here, you must make it through the gates after the first bull but before the last, so in a stupid attempt to keep running while holding a camera high above the crowd, I glance back briefly to see how close the rest of the herd is behind me.

I run straight into a pile-up of runners and end up in the tangle as others come crashing down in turn.

A second portion of the herd has now passed Dead Man’s Corner behind us – so named for its 90-degree turn where the bulls often loose their footing and slam into the wall.

With fear now coursing through my body and the realisation I’ll either miss out making it into the arena or, worse, get trampled or gored by a bull, I struggle to my feet and somehow, amid the chaos, I’m able to sprint through the last bottleneck into the packed arena, where wide-eyed runners stand scattered and exhausted, and those in the safety of the stands above roar in anticipation of seeing the bulls wreak more havoc.

Fight to the finish

When all six bulls have made it into the bullring corral, they’re released one at a time, back into the hordes.

Caught in the crush around the fringes of the bullring, I end up with moments to make way as the first of the crazed beasts sweeps around the edge.

Exhaustion grips the next beast as he falls on his side.

A maverick tourist ignores tradition and tries to “grab the bull by the horns”.

An instant chorus of whistles and jeers erupts from the stands, as enraged Spaniards pelt the offender with bottles as he flees the arena.

It’s hard to believe that in a matter of hours these same six bulls will burst back into the ring to face a certain end at the hands of a matador.

These bullfights are still the most contentious events of the fiesta – revered by traditionalists, slammed by animal rights activists.

The crowds soon spill back into the streets at the completion of the afternoon bullfight.

No time to rest though – there’s more music, dancing and sangria on the cards. Best just to make like the locals and paint the town, and everyone in it, pink.

» Dan Imhoff travelled with PP Travel (020 7930 9999; pptravel.com). Trips to the Running of the Bulls start from £129.


Rules of engagement 

How to run with the bulls

■ Have a look at the course beforehand (at least on a map) and decide where you want to run from. The danger spots are the first uphill stretch along Santo Domingo and the bottleneck entrance to the bullring.
A 90-degree bend known as Dead Man’s Corner is also one to avoid, as this is where the bulls tend to slip and often hit the wall.

■ Decide which day to run on. The first day
is most crowded.

■ To participate, enter the Plaza Consistorial before 7.30am through the gates on the square, before the run begins at 8am.

■ Four rockets will fire, the first to announce the gates are open, the second to let you know the herd has left the corral, the third to indicate the bulls and oxen have entered the bullring and the final rocket to signal the herd has entered the corral at the bullring.

■ Don’t grab the bull by the horns.

■ Be especially wary of the bulls if they end up separated and on their own.

■ Don’t run into the ring in front of the first bull.

■ Don’t attempt to do the run if you’re drunk. You aren’t invincible and won’t be allowed to run.

■ Don’t think you’re a matador and try diving over the bull if it’s hurtling towards you.

■ Don’t try to jump the barriers until the bulls have passed or until you reach the bullring.

■ The gates to the arena close after the last bulls have entered so if you want to make it inside don’t fall behind them.

Where to get the best view

To get a good view of the bull run from the street barriers, find a position at least 1.5 hours before the start. In the bullring, watching from the open terrace is free, while a ticket for the upper tier costs €4.

What not to do

Drunk tourists take turns climbing the statue of St Cecilia. The brave, or stupid, who reach the top, launch themselves above the crowd, where two rows of people below link arms to cushion the landing.

The catchers don’t always stick around and occasionally you will feel the thump across the cobblestones after someone’s landing has gone awry.

Danger Zone

■ Fifteen people have been killed during the running of the bulls since 1900, with more than 200 seriously injured.

■ Last year a 23-year-old Irishman died after falling from a 30m wall surrounding the old quarter.

■ The last fatality from a goring was in 1995.

■ The total course is 825m long and takes about four minutes.