Is it safe by todays standards ?
I use personal experience to answer that question. 1990 I was involved in an accident with my first mini and a Datsun. I was hit in the door by the front of the Datsun at a 4-way intersection. The speeds involved were approx 80 km/h. The occupants of both cars were fine and the mini was repairable. The Datsun was scrapped!
The secret of the mini's strength lies in its shape and weight. I was pushed across the road thereby reducing the force of the impact. The smaller the panels and the more square, the more strength the car will have.
My mini was old - todays have added protection from side impact bars and airbags so I would say that the car is not any less safe than any other small to medium size car on our roads today.