A summit kept deliberately bare

Primrose Hill rises to a little under 63 metres above sea level, which by the standards of London's high ground is unremarkable. What makes it exceptional is that the ground falls away cleanly to the south, and that nothing has been allowed to grow up and block the view.

That is not an accident of nature. The summit is one of the small number of officially protected viewpoints in London, and the sightline from it to St Paul's Cathedral is a protected vista: new buildings in the corridor between the two cannot be permitted to obstruct or crowd the cathedral's dome. The Royal Parks, which manages the hill, keeps the trees on the slope low for the same reason. The bareness of the top of Primrose Hill is a maintained condition, renewed every year by someone with a saw.

Blake and the spiritual sun

The hill's association with light is older than the skyline it now frames. William Blake, who knew this ground when it was still open fields on the northern edge of the city, told the diarist Henry Crabb Robinson that he had conversed with the spiritual sun and had seen him on Primrose Hill.

The remark survives because Crabb Robinson wrote it down, and it is now set into a York stone marker at the summit, where it is read by several thousand people a week who have climbed up for a view rather than a vision. It is a rare case of a piece of visionary poetry ending up as public signage, and it has given the hill a reputation for a particular kind of watching that predates photography by a century.

Robed bards and the turning year

Blake was not the only person to treat the hill as ceremonial ground. In 1792 the Welsh antiquarian and poet Iolo Morganwg gathered friends on Primrose Hill for the first meeting of what became the Gorsedd of the Bards, laying out a circle of stones with a larger one as an altar and reciting Welsh poetry and history.

Accounts differ on the details, including whether the founding meeting fell at midsummer or at the autumn equinox that September, and the ceremony's supposedly ancient druidic form was substantially Iolo's own invention. What is not in doubt is that a solar turning point was the occasion, and that Primrose Hill was chosen for it. The Gorsedd went on to become a permanent institution of the National Eisteddfod of Wales; it began on a north London hillside.

Where the light falls on the skyline

The practical reason the hill works so well for sunrise and sunset is geometry. The panorama faces broadly south, across Regent's Park to the West End and on to the City, taking in St Paul's, the BT Tower, the London Eye, the towers of the City and, on a clear day, Canary Wharf away to the east.

Because London's sunrise and sunset points swing a long way along the horizon through the year, the relationship between the sun and that skyline is never the same for long:

Bonfires, fireworks and the crowd at the top

Because the view is free and unobstructed, the hill has long been a place where Londoners gather for anything that happens in the sky. It had a rowdy reputation well before that: the Royal Parks records duels and prize-fights on the ground, which was bought from Eton College in 1841 specifically to give the people of north London somewhere to take the air.

The modern version is New Year's Eve, when tens of thousands of people have climbed the hill to watch the fireworks along the river; a recent year saw crowd figures reported at around thirty thousand. The scale eventually became its own problem, and in recent years the Royal Parks has closed the hill on Bonfire Night and New Year's Eve on safety and crowd-management grounds. It is a peculiarly modern outcome for a viewpoint whose entire value lies in being open and empty.