This part of GOV.UK is being rebuilt – find out what beta means

HMRC internal manual

Double Taxation Relief Manual

Saudi Arabia: Teachers and researchers

The agreement contains special provisions concerning teachers and researchers (Article 21). It provides a two year tax exemption for UK and Saudi Arabian resident individuals who visit the other country for the purpose of teaching or engaging in public interest research at a university, college, school or other recognised educational institution. The exemption relates only to remuneration derived from such teaching and public interest research.
Unlike many other similar provisions in other treaties, the Article does not contain a condition that, to receive the exemption, the teacher or professor must stay in the other country for only two years. So, if the individual does stay longer, they will not lose the exemption for the first two years of the visit.