B was convicted of unlawful killing and asked L to petition the king on his behalf. L was successful and B offered him £100 a reward, but later refused to pay. The court ruled that in general “a past benefit cannot be invoked as consideration for a future contract”. However this principle didn’t apply where (1) the past benefit had been at the request of the party who received it AND (2) where there was an understanding/expectation that there would be a reward in the future (in this case created by the subsequent promise of B), the past consideration could be “assumed” into the agreement.
