It is relevant that Thatcher is making this remark to Carpenter the poacher, because it is a line from the chorus of an English folk song called ‘The Lincolnshire Poacher’:
When I was bound apprentice in famous Lincolnshire
Full well I served my master for more than seven year’
’Til I took up to poaching, as you shall quickly hear
Oh ’tis my delight on a shining night
In the season of the year!