Still standing tall a full century later: Exploring the history of Northern Ireland's mighty Mourne Wall

The Mourne Wall is a feat of manpower; a tangible testament to the brawn and grit of the men who created it.

And to mark the 100th anniversary of its completion, the News Letter has spoken to the man in charge of its modern-day upkeep: Michael Donnelly of Northern Ireland Water.

Whilst similar walls exist in places like the Cotswolds in England, Mr Donnelly believes that the Mourne Wall stands alone in the British Isles in terms of the sheer ruggedness of the terrain it traverses.

Well over 6ft tall for much of its 22-mile length, and perhaps a couple of feet wide, the wall stomps across the crests of the Mournes' most punishing peaks, including Donard (850 metres high, 2,890ft), Commedagh (767m, 2,516ft), and Bearnagh (739m or 2,425ft).

There are only a handful of places where the builders were unable to make the wall stick, such as Hare's Gap near Bearnagh; there, in the saddle between two mountains, it looks as if the wall has tried to scale sheer rockfaces, but was honourably defeated by physics.

Mr Donnelly said that shortly before the turn of the 20th century, several thousand acres of land had been placed under the control of something called the Belfast City and District Water Commission.

"With the industrial revolution, Belfast's population was growing," said Mr Donnelly.But the city lacked a large-scale clean water supply.

Planners decided that their best option was to harness the watershed of the Mournes to create reservoirs, and pump the water to the city.

On the ‘inside’ of the wall, the parts which face towards Ben Crom and Silent Valley reservoirs, the land is owned by NI Water.

On the other side it is owned by a patchwork of interests, including farmers and the National Trust.

The wall, Michael Donnelly of NI Water said, basically existed to keep sheep off any slopes which led down to the reservoirs.

That's because, back then, there was no proper water treatment, so it was essential to make sure dung and dead animals never leached into the water supply.

Asked why a massive stone wall was used to stop sheep, instead of something less severe, Mr Donnelly put it down to “the overkill or grandeur that was the style of the Victorians”.

He also said relatively little is known for certain about the construction, like how many men were employed on the project from 1904 to 1922.

It is presumed that pack animals played a big part in the construction, but a lack of documentation leaves question marks over the exact methods used.

In recent times, a helicopter has been used two days per year to dump giant sacks of stone (totalling 300 to 400 tonnes in all) next to sections that need repair.

However, the local stonemasons from Thomas Rooney and Sons still must walk up to the wall on foot each day to stack the stones – a steep climb of at least an hour.

And once there, some of the capping stones which top the wall weigh upwards of 120 kilograms (almost 19 stone).​​​​​​​

One recent repair programme involved restoring 2.5km of wall (1.6 miles).

The cost? About £2m.

Mr Donnelly estimated that the cost of actually building the whole thing today would be "getting on £50m, I'm sure".

He said that there is not just a "moral" obligation to repair the wall, but a legal one – it is a listed building since 1996.

"It's really a Northern Ireland icon," he said, comparing it to the Giant's Causeway or Titanic.

"It's part of our heritage. If that piece of legislation [on listed monuments] stays intact, it'll secure the maintenance of the wall.

"As a society advances more, it regulates more. If I was a gambling man, I'd say the regulations would always be maintained, if not get more stringent.

"So I'd say the Mourne Wall will be here forever and a day."

The wall itself is not the only stone monument of note in the Mournes though.

Some of the mountains are topped by cairns of loose stones – or two cairns in the case of Donard.

Both are recorded prehistoric archaeological monuments.

The south-west side of the summit is crowned by the ‘Great Cairn’ (dating back to 3,300-3,000 BC), and houses Ireland’s highest passage tomb.

To the north-east is the ‘Lesser Cairn’ (c.2,300-1950 BC), which overlooks Newcastle.

More from this reporter:

Number of murals on public property growing – and loyalist ones far outnumber republican ones

‘Holistic and inclusive, inclusive and holistic’: Northern Ireland Office report so filled with ‘lazy jargon’ it makes you ‘lose the will to live’