http://en.wikipedia.org/wiki/Bloody_Code
Apparently "theft of goods worth more than 12 pence, which was only about one-twentieth of the weekly wage for a skilled worker at the time" could lead to the death sentence.
Other crimes that could be punished with death included:
- Being in the company of Gypsies for one month
- Strong evidence of malice in a child aged 7–14 years of age
- Blacking the face or using a disguise whilst committing a crime
The latter comes from the Black Act, which introduced 50 such offences:
http://en.wikipedia.org/wiki/Black_Act
"Pleading the belly" was an option for women who were detectably pregnant, and if they were found pregnant, the woman's death sentence could be postponed until they had delivered their child, changed to penal transportation, or even pardoned altogether:
http://en.wikipedia.org/wiki/Pleading_the_belly
A jury of matrons would be responsible - sometimes corruptly - although a woman would only receive one reprieve; any further pregnancy would be ignored and the death penalty carried out regardless: