 However , in R v. Hill and Hall ( 1989 ) , the Court of Appeal introduced an objective element to part ( b ) of the defence . The defendants had been convicted of possession of a hacksaw blade outside a US naval base in Wales , having admitted an intention to use the blade to cut through the base 's perimeter fence . They claimed a lawful excuse in that they had acted to protect their own property located near the base ; their reasoning was that the base would at some point in the future attract a nuclear attack by the Soviet Union . Given that Hill was " forced to admit that she did not expect a nuclear bomb to fall today or tomorrow " , the Court concluded that this threat to property was too remote and thus the defence had not been made out , however honest the belief had been . 
