"the British Library"

The British Library, St Pancras, London
GNU Free Documentation LicenseThe British Library, St Pancras, London - Credit: Ziko van Dijk
The British Library is the UK's national library. In 1986, the period in which Possession is set, the British Library was housed within the Reading Room at the British Museum in Bloomsbury, London. In 1997 the books were moved to a new purpose-built home in St Pancras, London. The British Library now holds in excess of 150 million items (including 14 million books) and is one of the largest research libraries in the world, spread across several sites in the UK.

British Library website