A fragment of the metal casing of the incendiary bomb which came through the North window of the Dining Room during World War II. It burnt a hole in the edge of the mahogany window-sill at the east end which is still visible.

The relevant extract from the Minutes of the meeting of the Trustees on 25 September 1940 reads: 'The Curator reported that on the night of Sept 8-9 windows and skylights had been damaged, in some cases blown in, by air blast. This damage was at once repaired with plyboard & asphalted felt. Exhibits had been moved away from the windows and the rooms were consequently upset. On Sept 24-25 a firebomb had shot through the plyboarding of the back window of the Library on Ground Floor, had burnt a hole in the 1822 Carpet and the boarding and one joist of the floor. As the floor was solidly constructed with pugging it had not penetrated the ceiling below. It was decided in consequence of the above and of the general situation not to have Public Days on Thursdays and Fridays in October & November ...'.

A more vivid account has survived in the wartime recollections of Rita Garrett, daughter of Charles and Lillian Cole (he was Resident Porter 1936-1946). During the war her parents lived in the basement and Rita, having been appointed the Museum's maid at age 17 in 1937, lived in a bed-sitting room in the Attic. The following notes were written up by Helen Dorey after Mrs Garrett visited the Museum in 1995:

The Cole family did not stay in the Museum during air raids. The building which is now Equity and Law, formerly the Equity Hall and the Canadian Air force HQ during the war [20 Lincoln's Inn Fields], had a shelter in the basement and anyone from the square was welcome (mostly caretakers) ... The night of the land mine was 23rd September 1940, Mrs. Cole's birthday ('what a birthday!' as she said afterwards). When it fell they were in the basement at Equity Hall. On emerging they saw other people, who had been in the public shelters dug in Lincoln's Inn Fields, coming out from under the grass like little rabbits. Terrible sights all around - the cab drivers coffee house blown away, ... - quite appalling. Remembers vividly the terrible smell - from the phosphorus in the incendiary bombs - and the square being full of fire engines. Mrs. Garrett & her boyfriend (later her husband) had intended to go for a stroll but changed their minds when they saw the state of the square. On returning to the Museum they found the front door blasted open and heard the crackling of an incendiary bomb on the ground floor. It was in the Library Dining Room beneath a pembroke table which stood in front of the north window sill (she thinks the one now in the South Drawing Room) - burning away just like a sparkler. The fire brigade came, with their pickaxes, all prepared to cut out the burning floor boards until appealed to by Mrs. Garretts father not to cause damage. Once this bomb was put out they immediately heard a second one crackling upstairs - this was in the South Drawing Room, in almost exactly the same position but on the first floor'.

It appears that the staff were in the shelter at 20 Lincoln's Inn Fields when the first incendiary bomb landed, returned to find it burning and called in the fire brigade to put it out – and then to extinguish a second one on the first floor above. Presumably it was Mr. Cole who collected this tail piece initially and handed it to Arthur Bolton, the Curator.

Taking Good Care: Exploring the Building Archive, Sir John Soane's Museum, London (online exhibition), 1 June - 30 June 2021