Doorbell transformer with a vitreous ceramic base
The logo in the centre is a globe with an arrow through it, and the words 'Golden Arrow' over the front.
The output terminals are on the right, and provide a selection of voltages (3V, 5V or 8V).
The round logo is the word 'ENGLAND' with the letters 'JB' in the centre.
The metal part to the left-centre of the picture may have been a metal earth strap, which would have extended upwards across the base and through the small gap in the outer edge. Howewver this was missing when this item was found, so no way of knowing for sure.