The rare sight of a woman at the wheel of a car on a Saudi Arabian highway has emerged on a video which shows other drivers giving her the thumbs up in support.

The woman who defied Saudi conservative conventions, is shown on video driving alone in broad daylight wearing a black face veil.

The reaction of other drivers is captured on camera with occupants of an overtaking people carrier, including a child, leaning out windows with their thumbs aloft.

Two men occupying another vehicle also give the unidentified woman the thumbs up, in the video that went online yesterday.

Arabic captions on the video say. “We depend on God; families are expressing their support. Men are in support!”

There is no specific law banning women from driving in Saudi Arabia, but they cannot apply for driving licences and have previously been arrested on charges relating to public order or political protest after getting behind the wheel.

The video comes ahead of a campaign by female activists on 26 October to push for an end to the ban. Previous campaigns, in which women have defied the law to drive in public, have ended with arrests of participants.

Conservative Saudis say letting women drive would encourage the sexes to mix in public unchaperoned and thus threaten public morality, but it is an important demand of many women who now rely on expensive private drivers to perform basic daily tasks.

Under Saudi Arabia’s rigid wahhabi school of Sunni Islam, women fall under the legal authority of a male relative, known as their “guardian”, who can stop them travelling abroad, getting a job or opening a bank account.

But there are signs that the attitude of authorities is changing.

On Tuesday, female members of Saudi Arabia’s influential Shoura Council which advises the Saudi King Abdullah proposed allowing women to drive.

The council is the nearest the kingdom has to a parliament, although its members are not elected but appointed by the king, and cannot make laws but only issue recommendations. However, these recommendations have often in the past prefigured Saudi reforms.

The proposal on women drivers follows other cautious moves by King Abdullah aimed at giving women more say, including the decision to appoint them to the council.