Two runaway horses caused travel chaos on the M25 today, leading to delays of up to six hours in both directions.

Police were forced to shoot one of the horses, after it broke free from being herded to safety and staggered onto the motorway.

Police had managed to herd the two animals off the Junction 30 sliproad to the M25 after being called to reports of two loose horses at Thurrock Motorway Services at 6am.

A vet had been rushed to the scene to sedate the animals but despite being heavily sedated, one of the horses managed to wrestle free and made a bolt for the M25.

Trained firearms officers shot the animal once it reached the motorway, a police spokesman said, “for the safety of motorists and to prevent further suffering to the horse.”

Police and the Highways Agency closed the sliproad approaching junction 30 this morning and this afternoon, causing widespread traffic delays in the area.

It was re-opened at 2.15pm but drivers were left stuck in gridlock around the area for hours.

One motorist from Canvey Island was left “fuming” after he left home at 10.30am and was only on the other side of the Dartford Tunnel by 3.30pm – leading him to miss his flights at Gatwick.

He said: “I’m absolutely fuming, there’s been no police, nothing at all for three and a half hours.

“We have missed our flight and our insurance company have just said we are not insured for a no show, even if there are horrendous accidents, which is unbelievable.

“We were totally gridlocked for five hours.

“I think the police are at fault. I only saw one member of the police come down to see what was happening.

“I have always paid my taxes, and this is the first time I have ever missed my flight. The traffic is absolutely horrendous, bearing in mind the traffic was held up for four hours.

“Are they going to be prosecuted these horse owners? If they are travellers, they think they can do what they want. If they’re a tax –paying person they would have to face the law.

“That’s what this country has come to. Where does the law come down?”

The accident came on top of an earlier collision between a lorry and car at 12.20pm today on West Thurrock Way, which caused no injuries, but also contributed to widespread delays on both sides of the Dartford crossing.

The link road between Junction 31 with Lakeside shopping centre and Junction 30 to the A13 remained shut until 2.15pm.

A spokesman for Essex Police said: “Officers said they have been contacted at about 6am on August 5 with reports of two horses running loose at Thurrock Motorway Services off the M25 in Grays.

“Police were forced to shut the slip-road off the M25 approaching Junction 30 to the A13 to prevent any accidents.

“One horse got loose and a vet was contacted to sedate the animal. Despite the best efforts of officers on the scene and the vet, the horse managed to get onto the M25 following sedation, causing the road to be closed at junction 30 at about 1.20pm.

“For the safety of motorists and to prevent further suffering to the horse, trained firearms officers shot the animal.”

The spokesman added that police were still enquiring as to who the owners of the loose horses were, before they could look at pressing charges.