Our attention has been drawn to a report on Saudi Arabia by the UN's Committee on Elimination of Discrimination Against Women, which contains the responses from a Saudi delegation to various questions posed by the Committee.
It's fairly heavy going (if you're feeling ambitious it's available online), but we were struck by a section towards the end where the delegation helpfully explain why women are forbidden to drive in Saudi Arabia:
"With regards to the issue of driving, in the early stages of Islam, there were no cars, and women rode camels or donkeys, and participated in all walks of life. This was history, and could not be forgotten. The matter was not related to Sharia. However, the problem was not related to the laws of the State, it was a matter for society. When people and the mentality were ready, then women would be allowed to drive cars. Once there was a need for women to drive, then it would be permitted. The Government was worried about women, and this was why those who were responsible were against the idea of women driving cars."
Which clears that issue up.