One of the key moments in the creation of the libretto for 17 Days was the discovery of the works of the English poet Charlotte Mew (1869-1928). I fell instantly in love with her direct, unadorned, yet deeply evocative style. So much so, that I ended up using two of her poems in 17 Days: Do dreams lie deeper and A quoi bon dire. Returning to her poems again several months later, I can see why - on a purely technical level - I was drawn to them. The line lengths are short, there are few awkward polysyllabic words (which play havoc with a beautifully shaped musical line) and the poems bloom with lovely long vowel shapes.

The subjects that she chooses to write about (at least in the poems I have chosen) are gently poignant, not railing against the Gods in any melodramatic way, but focusing instead on moments of keen longing. As an example, here's the last stanza of A quoi bon dire:

"And one fine morning in a sunny lane
Some boy and girl will meet and kiss and swear
That nobody can love their way again
While over there
You will have smiled, I shall have tossed your hair."

Incidentally, the first two lines of the poem as Mew wrote them are: "Seventeen years ago you said / Something that sounded like goodbye". In my setting I changed "years" to "days", the coincidence of the fact that the miners were trapped undiscovered underground for 17 days being far too strong for me to resist a little poetic licence.

Mew herself was a fascinating character: a fiercely private person, she kept her hair short and had a habit of wearing gentlemen's clothing. Her life ended in tragedy. Inconsolable after the death from cancer of her sister, Anne, Mew committed suicide by drinking Lysol (a cleaning detergent) in March 1928. She is buried alongside her sister in the north end of Hampstead Cemetery, NW6, not far from where Crouch End Festival Chorus rehearse today…

"And how does one bury the breathless dreams ? -
They are not of the earth and not of the sea,
They have no friends here but the flakes of the falling snow;
You and I will go down two paces -
Where do they go?"
(From Do dreams lie deeper? by Charlotte Mew)

Two children's choirs will be joining Crouch End Festival Chorus at the world premiere of 17 Days: Finchley Children's Music Group and Coldfall School Choir. I've always loved writing music for children's choirs because they invariably sing my music with touching enthusiasm.

Which isn't to say that writing for children is easy, not by any means. Writing a piece that is readily singable without patronising or talking down to the children is notoriously tricky. Writing such music within the context of a much larger fully 'grown up' piece is altogether more complicated.

In 17 Days, the children have a pivotal role to play. At the beginning they set the scene, playing the dual roles of news reporters flying in from afar to cover the unfolding crisis, and angels on high reflecting on the events. They sing: "News is coming in of a collapsed mine in northern Chile, which has left over 30 miners trapped. Nobody knows if they are alive or dead." Their unearthly tune is punctuated by violent outbursts from the brass and percussion and is constantly underpinned by the slightly menacing, propulsive rhythms swelling up from the adult choir. The children - and their melody - fly above it all…

 Later in 17 Days, the children again take centre stage in the setting of Emily Dickinson's poem, Hope. Here they sing:

"And sweetest in the Gale is heard;
And sore must be the storm
That could abash the little Bird
That kept so many warm.
I've heard it in the chillest land,
And on the strangest Sea;
Yet, never, in Extremity,
It asked a crumb of me."

Again the children's melody appears to lift them above the drama of the scene below, this time embodying Dickinsons "little bird" so abashed by the storm. The innocent and moving beauty of Dickinson's text is reflected in the abundant tunefulness of the children's melody and will be amplified further still by the natural innocence of their performance. It should be a magical effect - I can't wait to hear it!

Giving the miners a voice was one of the biggest challenges of 17 Days. In spite of the dozens of newspaper articles, books and documentaries that have been written to try to describethe miners' existence during the period before their discovery, there is still a hole at the centre of this story - the miners themselves have largely kept their pact of silence.

And yet I felt it was critical to the structure of the work that we reflect events from the miner's perspective below ground, so I commissioned the poet and playwright Carol Lashof to write a sonnet on that subject. The resulting poem, We live in mud, is the black heart of the piece. I've collaborated with Carol on a number of projects over the years, including two operas, and she has a very special ability to write not just great poetry, but also to write singable texts instinctively.

Here is a great example from halfway through the poem: 'Aloud I say that help will come, but fear, / like dust, comes in with every breath, and I -/ I am so afraid of losing you, my dear.' Elegant, simple, heartfelt verse with lots of generous vowel shapes - aloud, fear, breath, losing, dear - all absolutely perfect for me as a composer and also gratifying for the singers to perform.

CEFC are truly the most adventurous and exciting choir in the world at the moment and it's truly humbling to hear my music performed so beautifully at the rehearsals. All I can say is that it's going to be a very special concert indeed. Grab some tickets while you still can - I'll see you there!