[lsh123]

I found this wikipedia page: https://en.wikipedia.org/wiki/Anne_McLaren

There is a detailed year by year description of her work and I can't see how she could have "defected to Russia" except one note "...she was a member of the Communist Party of Great Britain..."

[ramchip]

There's more detail in various news articles following the accident, but also no mention of Russia.

http://www.telegraph.co.uk/news/obituaries/1556847/Professor...