WATCH: A match made in mud as happy couple join in fun run

Bride-to-be Karen Bill, from Shrewsbury, and her fiancé Dave Allen conquered thick swamps, treacherous climbs and chilly river crossings in the White Run at Eaton Mascott near Cross Houses.

Karen and her female pals donned full wedding dresses they bought from eBay, and they all looked resplendent in their immaculate white gowns before the starting gun. That did not last long.

WATCH: Splashing good fun at mud run

Their dresses ended up caked in mud after the fun, but gruelling course - yet Karen will have a new dress for the big day.

She and Dave, from Wednesbury, in the Black Country, are getting married at the Albright Hussey in Shrewsbury in May.

“Dave’s been running a while and I started in June,” she said.

"We joined an online running community called This Body Runs, who we’re here with today, and we just decided to have this as my hen do.”

The running-mad couple are even doing a race on their honeymoon, the Liverpool Half Marathon.

They joined around 300 hardy runners to burn off a few festive calories at this year’s event.

Athletes young and old lined up for the fun race which included lots of mud, hills, bogs, marsh land, lakes, river crossings, tunnels and even water slides.

While many of us were still sweltering under the weight of our lardy tums after a week or so of over-indulgence on turkey, brandy snaps and egg nog, this hardcore bunch completed the gruelling 5km course in spectacular fashion.

Some donned simple white shirts and shorts, others unicorn hats and karate bandanas.

Organiser Simon Macdonald from Ultimate Fitness Experience called everyone to the starting line and got participants up for it with a quick warm up which included star jumps and high fives, before they were off - charging up the hill like wild horses stampeding in the Arizona desert.

The first half of the course was mainly cross country running in boggy conditions, but as the route progressed, the obstacles came into play.

One of the most popular, judging by the laughter and occasional scream, was the water slide. It made a nice respite for the runners after a challenging river crossing and steep hill section, as runners hurtled down plastic sheets soaked in washing up liquid at what seemed like warp speed.

Such was the speed generated, some couldn’t resist blurting out an obscenity or two on their way down, while one cry of: “Oh, my balls!” was a particular highlight.

Simon picked the slide out as his favourite part of the course, and laughed: “It was 25m at the start of the day, but now it’s doubled in length!”

Next up for runners was a treacherous bog in which many became submerged waist deep.

It was all fun and games at first, but some competitors faces were etched in genuine terror as they tried in vain to haul themselves out of the gloopy mire.

Some needed rescuing with ropes, while others soldiered through, offering each other a helping hand and lapping up cheers and laughter from the sidelines.

GALLERY: Mud, glorious mud

A chilly river crossing caught out a few, with a dip in the middle causing runners to splash head first into water. Some used it as an opportunity to drench their pals who they deemed not messy enough, before embarking on the final steep climb.

Runners enjoyed rapturous applause as they approached the main field for the grand finale, a lake that was chest-deep for some, followed by dark, narrow tunnels ahead of the finishing line.

The wedding parade, their dresses heavy with mud and water, brought up the rear of the field, and many stayed back to cheer them on.

Simon confirmed that the event should be back again next year.

He added: “It’s been amazing. Everyone has had fun and there’s been loads of giggles along the way.”