AS the BBC Proms in London began with music commissioned from Scots composer Anna Meredith, partnered to visuals from 59 Productions, the movie for which she has written her first soundtrack, comedian Bo Burnham’s debut feature Eighth Grade, was opening to rave reviews in the US.

Those significant events out of the way, the high summer of Meredith continues with another incarnation of that Proms partnership to open the Edinburgh International Festival, with an orchestrated performance of her Scottish Album of the Year-winning Varmints following as part of the Festival’s Light on the Shore series of concerts in Leith Theatre, and then a Fringe run of six performances of Anno, her reworking of Vivaldi’s Four Seasons for the Scottish Ensemble with visuals by her sister Eleanor at Edinburgh’s International Conference Centre as a recording of that piece is released by Moshi Moshi.

It has not been a planned campaign exactly – the composer happily delegated the orchestration of Varmints for the Southbank Sinfonia to the other members of her own band, being pre-occupied with the EIF/Proms co-commission – but it is surely a happy coincidence that she will have such a high profile at Scotland’s premiere cultural showcase.

“I guess so,” she says. “It is nice to be so busy and to get to hang out in Edinburgh. I’m really happy that it is letting me show different sides of what I do. I’m very conscious that the opening event is not about me, but this is all a nice snapshot of the different work I do.”

That proviso about Five Telegrams, 2018’s large-scale free outdoor musical event to launch the Festival, is something about which she is adamant, regardless of the fact that it features, to my ears, some of her finest orchestral writing to date.

The other important partner in the creation of the work has been the 1914-18 NOW series of works marking the anniversary of the First World War. Although what the thousands of people who gather on the evening of August 3 will witness at Edinburgh’s Usher Hall is probably most like the first of the son-et-lumiere events created by 59 Productions, the performance of John Adams’s Harmonium to mark the 50th anniversary of the Edinburgh Festival Chorus, it is also the most textually-specific of any of them.

Meredith and Richard Slaney of 59 Productions worked closely together in the archive of the Imperial War Museum in search of inspiration, and their five-movement audio-visual composition only focused on the Great War’s methods of communication after explorations of geographical features of the battlefields, like rivers, had been rejected.

The composer explains: “We’ve been planning what it is going to be from about a year ago. We decided it would be five movements based on different forms of communication during the First World War, looking at censorship, codes, spin and hype. Once we found those five angles and before anything was visually made, I spent a lot of time with Rich planning things out in a graphic way, what the colour and drama of each movement was going to be.”

Central to the whole work, and the substance of the second movement, was the pair’s discovery of the “field postcards” printed, in diminishing sizes as result of a paper shortage during the conflict, for soldiers to communicate home.

Slaney now has a number of them, fascinated by the exact correlation of the dates they carry and ones in his own diary for work on Five Telegrams, sometimes precisely a century apart.

“They are not collectors’ items because there were so many of them, and I got these for a pound each on Ebay. Field postcards were these multiple choice postcards that soldiers could send back from the front. They could only use these options of text, so it didn’t take as long to censor as a long love-letter. It is sort of the equivalent of sending a text home just saying ‘I’m safe’, or like a status up-date on social media, or using emoticons.”

At all points in their explanation of their work, Meredith and Slaney are at pains to point out the parallels between their researches and our own time. Their treatment of the texts of these postcards will appear in visual form in the projections on the Usher Hall and sung by the National Youth Choir of Great Britain, whose performance was recorded at the opening night of the Proms. As Meredith says, the spare nature of what the soldiers were permitted to say is “heart-breaking”, but especially in the context of the performance.

“The National Youth Choir of Great Britain are about the same age as these soldiers would have been.”

There are young people involved throughout the work, with brass and percussion players from the BBC Proms Youth Ensemble augmenting the BBC Symphony Orchestra under conductor Sakari Oramo. Ten extra trombones lined up in front of the organ in the Royal Albert hall for the opening movement, entitled Spin and concerned with the reporting of the war, with over-exaggerated claims and what might now be termed “fake news”. Slaney, however, draws a distinction between the hype and lies of today and over-blown rhetoric of a century ago, when, he says, “newspapers were more concerned with helping to keep morale up.”

The third of the five movements is concerned with redaction, and again Slaney has century-old communications to illustrate the pair’s ideas, picture postcards of the gardens of pretty French villages with the name of the actual location carefully obliterated by the censors.

For their work, says Slaney: “Anna wrote a theme and then cut bits out of it, or obscured it by other bits in sound.”

Adds Anna quickly, in a way that eloquently illustrates the partnership: “And that same process is matched note-for-note by the visuals.”

There are nods to code wheels, semaphore and Morse in the fourth movement, Codes.

“Musically there are lots of simultaneous patterns trying to lock into each other and find a beat,” says Anna, “rhythms running each against other. It ends in moment with extra percussion and trumpet players in boxes at the side, fighting against each other. And that has been mirrored exactly in the visuals, so it makes that process very clear.”

Slaney calls the end result a “hobbled waltz”, arguably improving on Meredith’s description of her own music as a “mutant lumpy thing.”

Armistice, which concludes the work, is based on very specific intelligence about how the event we mark every 11th of November played out for the first time.

“It is about a particular moment in time that needed to be communicated, and the fact that the war ended in that way,” says Slaney. “The decision to stop fighting was taken 36 hours before it came into effect and that had to be communicated. In those 36 hours thousands more people were killed.

“On the morning of the 11th, the amount of artillery fire significantly increases. There was apparently an American general who went on the attack, wanting to have achieved something before he went home, and two and a half thousand Americans were killed that morning.”

Meredith adds: “Soldiers didn’t want to carry munitions home with them so they fired out all their ammo. I was clear to me that Armistice was not all flag-waving and bells, but more exhausted and hollow, with a lot of mistakes made. The troops who joined up last were sent home first, while some guys who had been there longest were still out there a year later. So there is a heavy cumulative build in the last movement, but quite a spare ending.”

It is a message that she hopes the performance gives space for the audience to come towards, rather than having it pushed on them.

Slaney adds: “The redrawing of borders after that war is still causing conflict. Although it is not in living memory any more, it is still having an effect. The First World War is not as far away as you think and the communication technology it used not so very different.”

Anna Meredith and 59 Productions’ Five Telegrams is the Standard Life Aberdeen Opening Event of this year’s Edinburgh International Festival at 10.30pm this Friday (August 3).