I wonder if you could do a drawing for me of an explosive slab of chocolate

On this day in secret letters

Lord Rothschild to Laurence Fish, 4 May 1943.

Born in London in 1919, Laurence Fish was a commercial illustrator known for his impeccable graphic design and technical drawing skills. During his long and distinguished career he attracted commissions from many of the UK’s largest companies, designed countless magazine covers and award-winning posters, and saw his work exhibited at such institutions as the Royal Academy and the Royal Institute of Painters. His most important commission, however, arrived by letter at the height of World War II, written in a secret bunker by the head of MI5’s counter-sabotage unit in response to an ultimately fruitless Nazi plot to kill Winston Churchill by chocolate bar.

Fish, who at the time was in the RAF, was keen to help, and provided a drawing that can be seen below. It was declassified in 2005. The letter itself was later found in Fish’s papers by his wife, Jean, following his death in 2009.

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4th May 1943

Dear Fish,

I wonder if you could do a drawing for me of an explosive slab of chocolate. We have received information that the enemy are using pound slabs of chocolate which are made of steel with a very thin covering of real chocolate. Inside there is high explosive and some form of delay mechanism, but we do not know what, so it could not be put in the drawing. When you break off a piece of chocolate at one end in the normal way, instead of it falling away, a piece of canvas is revealed stuck into the middle of the piece which has been broken off and sticking into the middle of the remainder of the slab. When the piece of chocolate is pulled sharply, the canvas is also pulled and this initiates the mechanism. I enclose a very poor sketch done by somebody who has seen one of these. It is wrapped in the usual sort of black paper with gold lettering, the variety being PETERS. Would it be possible for you to do a drawing of this, one possibly with the paper half taken off revealing one end and another with the piece broken off showing the canvas. The text should indicate that this piece together with the attached canvas is pulled out sharply and that after a delay of seven seconds the bomb goes off.

Please return the enclosed drawing.

Yours sincerely,
Lord Rothschild

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Illustration by Laurence Fish, 1943.

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The letter above can be found in the book, Letters of Note: Art.