The Pulpit, St Paul's Cathedral Churchyard

Liquidambar styraciflua / Sweet gum

I arrive at seven o'clock on a Sunday morning, an hour before Holy Communion. Cheapside is deserted and beer cans rattle around in the cold November wind. Crossing to the south side of the churchyard, I find a sweet gum in seasonal attire. 

Liquidambar styraciflua is the crimson king of autumn, and the tree rises in the join between choir and transept, its foliage stark against the stone walls. Nearby a woman sips coffee in the shadow of an aspen. The benches below the sweet gum have been bombed by pigeons and their painted boards fail to tempt passers-by.

Cautiously, I step over a small fence guarding a flower border and start to climb the north side of the tree. Crawling up a steep incline to a lone branch, I swing around to the southern face. The scale of the cathedral wall is terrifying, and ascending the tree feels like climbing the mast of a sailing boat in the lee of a giant container ship. After a desperate scrabble, the cathedral dome appears through a blood-red ceiling of leaves. 

In spite of numerous branches higher up, my heart is pumping as if gripped by a fever - I have never been more terrified or determined. I look down at the churchyard, where a splayed sculpture of Thomas Becket lies prostrate on the lawn, arms raised in defence. The head of the statue is thrown back, open mouthed, more like the cry of a man falling to his death than the face of a martyr at the altar. My fingers tighten around the trunk and my nails dig deep into the bark. No one would beatify a man for falling from a tree. 

Overhead the great cathedral bells begin to chime the morning call to prayer. In my current state the sound is like a death knell and John Donne's famous words fill my agitated mind: 'Never send to know for whom the bell tolls; it tolls for thee.' The poet's own memorial lies a stone's throw away within the cathedral's nave.

I inch higher, and these fearful thoughts are banished on drawing level with the giant face of a cherub, a carving fixed to the cathedral wall. Roofline statues may be imposing viewed from the ground, but up here the angelic child wears a stupefied expression. 

I dare not test divine patience or my own human strength by climbing to the zenith, and begin a long retreat the way I have come, trying to glimpse worshippers through the amber glass windows of the east end. 

Back on the first branch I hang like a grape, dangling with the intent to jump down - what little I can see over my compressed chin seems impossibly far away. Finally, exhaustion forces me to abandon myself to fate. I drop with a hollow thud onto holy ground.