As well as being the only student to attain that grade that year she was also one of two students to be awarded a prize and special commendation for the degree she has completed in two years instead of the usual three.
The teenager who never went to school and was tutored by her father Harry Lawrence - said that the result was much as she had expected.
Mr Lawrence has been his daughter's companion and attended all of her lectures and tutorials at university. They arrived at the Examination School together on a tandem bicycle to see her results posted on a board.
Ruth gained her PhD in 1989 and went to work at Harvard in the US. Her father went with her. From 1993, in her mid-twenties Ruth was a professor, at the university of Michigan studying knot theory. In 1998 she married a mathematician at the Hebrew University at Jerusalem - Ariyeh Neimark - who is six years younger than her father. The couple have two children. Since 1999 she has been Associate Professor of Maths at the Einstein Institute of Mathematics, part of the Hebrew University of Jerusalem where she is known as Ruth Lawrence-Neimark.
Click on the link below to watch a video clip of Ruth talking to Breakfast Time co-presenter Sue Cooke. (First broadcast 4 July 1985).http://www.bbc.co.uk/mediaselector/check/player/nol/newsid_6490000/newsid_6497000?redirect=6497061.stm&news=1&bbram=1&nbwm=1&nbram=1&bbwm=1