Ink pad stamp, reading “I certify that this is a true and correct copy of the original”. The stamp is a Printy 4912 made by Trodat.

Part of the Stephen Hawking Office acquisition was not in the office at the time, but had been kept for historical purposes by the Stephen Hawking Archive. This included older communications equipment. The majority of such equipment is electronic, but the collection also includes a selection of items used by Hawking to provide his physical signature.

Stephen Hawking's signature became increasingly illegible as his disability progressed, and providing it became a considerable effort for him. In order to facilitate his administrative duties, he shifted to using his thumbprint in combination with several accompanying stamps, such as those explaining the purpose of the thumbprint, and those accompany the signature of witnesses. In the late 1990s Hawking also used a stamp that reproduced his handwritten signature from the 1970s, in which the progress of his disability was already visible.