Cathy

Cathy Salt was a journalist who worked as the science correspondent for the Cardiff Gazette. Around June 2006, she was pregnant with the child of her boyfriend Jeffrey. She became engaged to married to him, ostensibly to stop Cathy's mother from nagging, but the baby that was due "sort of clinched it".

In September, she investigated the new nuclear power station and came across Mr Cleaver's internet page. This page told her the plant was not safe — indeed, it would destroy the whole of Cardiff. Subsequently, she went to a press conference held by the Lord Mayor, Margaret Blaine.

When she pressed Blaine for an explanation for all the deaths associated with construction of the plant, the Lord Mayor claimed they were all accidental. Blaine took Cathy aside for a private interview in the ladies' toilet. In the privacy of her stall, the Lord Mayor removed her skin suit to reveal she was a Slitheen. She planned to kill Cathy, but when Cathy revealed she was pregnant and was going to marry Jeffrey the 19th of the following month, "Margaret" was moved to spare her life.

Biography from the TARDIS Data Core article, licensed under CC-BY-SA