This series consists of nominal index cards relating to SOE personnel and contacts in Scandinavia and to German personnel and suspected or known collaborators who had come to SOE's attention. The cards are mostly typewritten with manuscript additions and amendments, and many are endorsed 'Bayswater index', though it is not clear that these ever formed part of a separate index.
There are two sorts of card, distinguished by colour. The white cards mostly relate to SOE personnel or friendly contacts, although there are a few white cards about German or collaborating subjects. The cards list the name and nationality of the subject, and give details of the subjects' activities, membership of resistance organisations, the operations they took part in and, sometimes, more general biographical detail. The cards often include references to SOE files.
The pink cards relate to Germans based in Scandinavia and to known or suspected collaborators, and give detail of nationality, some biographical detail and information about how the subject came to be known to SOE, again with reference to SOE files sometimes being given. Presumably because of the importance for personnel going to Scandinavia being able to recognise the subjects of these cards, physical descriptions are also sometimes given. The few white cards relating to Germans or Scandinavian collaborators contain similar details.