“On 14^th April 1913 a small, oval-shaped, cream tin, containing a charge of gunpowder with an electrical firing system, was discovered by the police at the Bank of England and, after removal to a police station, it was rendered safe.  Most of the explosive was removed and the remains of the device now reside in the City of London Police Museum”.
Above extract from “London: Bombed, Blitzed and Blown-Up” by Ian Jones MBE

And the remains of the device still reside in the City of London Police Museum and are on display in its new home at the Guildhall Library.

The discovery of this bomb resulted in several newspaper reports. There are variations in the accounts of what happened, as you might expect, but some basic facts are present in them all …..

The milk can was placed near to the Bartholomew Lane entrance to the Bank of England and was discovered around 3 pm on 14th April 1913. Some say it was a milk can hung on the railings, others say it was a brown paper parcel. A City of London Police officer, PC Ralph, who was on patrol in the area, became aware of the presence of the milk can and took steps to render it inert – there are accounts of the constable being seen dashing to a fountain in front of the Royal Exchange and plunging a smoking can in its waters. Other, less dramatic accounts say the bomb was immersed in water at Cloak Lane Police Station after the constable had carried it there. Certainly, immersion in water was, at that time, the standard way of rendering such devices harmless.

At first, the incident was regarded as more a mischievous practical joke than anything else, but subsequent investigations established that if the milk can had exploded the consequences would have been serious. This was not only due to the location it had been found – the area around Bank was, and still is, one of the most crowded parts of the City – but also because, upon examination, this milk can bomb was found to be a very sophisticated device and only failed to operate because of a tiny flaw in its construction.

As the device contained two women’s hat pins – both reportedly holding a watch in position – and gunpowder (a favourite main charge of other Suffragette devices), and also was similar in design to a Suffragette bomb that had exploded a few days previously at Oxted Railway Station, it was believed it was their handiwork . It was also taken as evidence that they were becoming more indifferent to causing injury and damage.

Select Bibliography:
“London: Bombed, Blitzed and Blown-Up”, Ian Jones MBE
Sheffield Evening Telegraph, 15 April 1913
Yorkshire Evening Post, 15th April 1913