Police officers had to put a 10 mile rolling closure into operation on the northbound lanes at Sandyknowes as they struggled to recapture the animals, which got loose after a truck and trailer overturned.

Bemused motorists watched on as the cows wandered in and out between cars on what is one of the busiest stretches of road in Northern Ireland.

Mid Ulster Assembly member Patsy McGlone was one of those caught up in the delay.

"I've never seen anything like it," he said.

"There was a bullock standing in the middle of the motorway staring down a policeman. The bullock wasn't moving and neither was the policeman.

"The two of them just faced each other off waiting for one to make a move."

Not content with disrupting motorway traffic, after around two hours on the run some of the cows made their way onto the Londonderry railway line.

A Translink spokeswoman said the stray animals had not caused any cancellations but that drivers had been advised to be on the look out.

No bull: roaming cows got loose after a trailer overturned

Earlier, PSNI officers on the M2 had tried to corner the four-legged fugitives by parking an articulated lorry across the lanes. However, it was to no avail as the cattle continued to elude capture.

SDLP South Antrim MLA Thomas Burns said: "I appreciate the surrealism of this incident is going to be the main talking point but I have warned repeatedly that there are insufficient contingencies in place to deal with accidents and traffic problems on the citybound stretch of the M2 from Sandyknowes in the mornings.

Tailback: frustrated motorists hoped cows would get a moo-ve on

"It doesn't normally take an escaped herd of cattle to bring the M2 to a standstill — one vehicle with a flat tyre is sufficient to bring the traffic to a halt. When an accident occurs on or close to Sandyknowes the whole system breaks down.

"We have lobbied the Minister repeatedly, urging him to be more flexible," he added.

Cow's that: one of the animals that caused the chaos