The box contains English Electric Company Bradford negatives in sequentially numbered envelopes in the BT/Dxx series:

BT/D60/1-55; BT/61/1-3, 5-11; BT/D62/1-32; BT/D63/1-33; BT/D64/1-33; BT/D65/1-12; BT/D66/1-70; BT/D67/11-14.