On the last weekend before England entered its second lockdown, two slabs of the Berlin Wall were standing on the concourse at Lewisham Shopping Centre. They marked the entrance to the Migration Museum, a roving exhibition space that has made a temporary home in south-east London, near a branch of Footasylum and a stall selling phone cases. Inside, the museum’s main space was laid out like an airport terminal, for Departures, an exhibition about emigration from the Britain, which has shaped the country’s history (not to mention the world’s) at least as much as immigration to it has. A short film took visitors on a brisk tour of the last 400 years, from early efforts at colonial ‘plantation’ in Virginia and Ulster, through to the 19th and early 20th centuries – when more than 17 million people left Britain and Ireland, mainly for North America – and the more recent period of free movement within the EU.