Sire is a C++/Python program which is distributed under the GPL license (initially GPL2, and GPL3 since 2022). This license was chosen to remove any complexity related to intellectual property claims made by the universities (predominantly in the UK) who employed the PhDs and postdocs (PDRAs) who contributed to sire's development. Sire started as a rewrite of the ProtoMS program that was written during the doctoral studies of Woods during an industrially funded PhD in 2003. At that time, few academic software were released under an open source license, and it was challenging to convince the University of the merits of releasing ProtoMS openly. Fortunately, the industrial partner on that project was supportive, and so an agreement was made that ProtoMS could be released under the GPLv2 as long as a contract was signed that forbade Woods, the University or that industrial partner from ever trying to separately commercialise the software. This was acceptable to all, and ProtoMS was released openly.