When an unmarked, unidentified parcel arrived at the offices of Mitzvah Day recently, they knew what to do. The man who came from the CST examined the package and pronounced his verdict: call in the bomb squad. And so the JW3 centre, where Mitzvah Day is housed, had to be evacuated, the Finchley Road closed and the suspect item dealt with in a controlled explosion.

When the remains were examined, they were found to have comprised a batch of Mitzvah Day’s own t-shirts, returned by an unknown— and likely to want to remain so — volunteer.