AA Travel announced that rush-hour traffic was at a crawl on Tuesday last week because the rambling reptile was causing vehicle obstructions on both the A24 and the A283 coming off the Washington roundabout.
Scores of people took to social media commenting on the incident - and others came forward worried that the wandering reptile could be their lost pet.
Among them was Frances Russell, who lives in Storrington Road, Washington, who was alerted to the drama by her grandaughter Jasmine Divitto.
Jasmine, 22, from Billingshurst, had spotted reports of the tortoise-tumult on Facebook and feared it could be one of her nan Frances’s eight pet tortoises.
“I went round counting them and thought ‘ah, we’ve got one missing’,” said Frances, 71 - who later did a livestock re-count and found all eight present and correct.
“I thought it could have been one of my females who is about seven years old,” said Frances, whose oldest tortoise is a male aged 80 whom Frances bought when she first moved to Horsham 32 years ago.
She was relieved when her animal stock-take later revealed that none of the tortoises were missing after all.
Meanwhile, other owners of lost pets were also worried that the road-roaming tortoise could be theirs. One man living near Washington roundabout said his tortoise had gone missing last year and had not been seen since.
Sussex Police said they received a call about the incident at 7.45am last Tuesday but could find no trace of the tortoise when they inspected the area half an hour later.
And the drama ended in mystery when the AA said that although it had received reports of the tortoise on the loose on the A24, no-one had been able to find it.
There was even conjecture that the whole thing might have been a storm in a teacup - and that the ‘tortoise’ could, in fact, have been a deflated football.
Leading animal charity, the Southwater-based RSPCA, said they had no direct reports of a tortoise on the road. A spokesman added:“If anyone spots this tortoise they can contact our hotline on 0300 123 4999.”