When we were eight everyone said we were “thick as thieves,” though we didn’t really know what that meant. Even though you were a tomboy for my ninth birthday you bought me a Forever Friends locket with your pocket money and kept half of it to wear around your own neck. Everyone was jealous of our friendship, it was such a precious thing – like gold.

But when we started secondary school things began to change. You stopped wearing the necklace, saying it was embarrassing and childish. I told you I’d stopped wearing mine too but I hadn’t-I just hid it beneath my shirt because I couldn’t bear to take it off.

You started hanging around with what my mum called “a bad crowd.” You got your tongue pierced, cut your shoulder length brown hair short and dyed it blue. You were unrecognisable to me as Sarah, let alone as my best friend. When I called you said you were busy, eventually you just stopped picking up the phone.

Because I wasn’t sporty or pretty or funny I found it hard to make friends. I wasn’t like you, with the “gift of the gab” as Auntie Lou used to call it. I ate my lunches alone. Sometimes I would catch you looking over at me with an expression that looked something like regret or sadness – perhaps guilt? – on your face, but no sooner had it appeared than it was gone again, hidden behind the tough girl mask which emotion could not crack.

I wasn’t bullied, at least. Why would the bullies be interested in me if nobody else was? I just existed in a perpetual state of nothing. And that hasn’t ever changed, perhaps unsurprisingly. When your life is a blank canvas what is there to excite you? I did the ‘normal’ things, of course, went to university, got a degree, moved to London, got a job. I even had some boyfriends though I wasn’t really interested in boys.

I often wonder this: If you’d known the path my life would take after you turned your back on me, would you still have done it? If you hadn’t taken off that locket, if you’d only loved me back in the way that I loved you, we could have been happy, you and I. But you did turn your back on me, and now I’m finally finding the strength to turn my back on you.

I will not send this letter, but rather burn it right before I cast my half of the locket off the bridge. And when I climb over the rail and follow it into the murky abyss, Sarah, I will take my leave of this world, of you. And I will be free.