This plaque was donated by the members of the Burlington Arcade Association to commemorate the sesquicentenary of the Arcade.
1819 - 1969
Unveiled 21st May 1969 by H.R.H. Princess Alexandra.
'Sesquicentenary' is such a great word - it's not even in the Microsoft dictionary. As you can work out it means the 150th anniversary.
Site: Burlington Arcade (1 memorial)
W1, Burlington Arcade, 4
Actually on the pillar between nos 3 and 4.