ELI5: Explain Like I'm 5

Williams v Roffey Bros Ltd

Okay so imagine you have a box of toys, and you promised your friend that you would give them a toy from your box if they did their homework. But then your friend did the homework, and you realized that you actually needed that toy for yourself later. What do you do?

That's kind of what happened in the case of Williams v Roffey Bros Ltd. There was a builder (Roffey) who promised to pay a carpenter (Williams) a certain amount of money to do some work. But as the work went on, Roffey realized that Williams was having some problems and might not be able to finish the job on time. This would have caused problems for Roffey, because they had promised to do the work by a certain date and would have to pay penalties if they didn't.

So, Roffey decided to pay Williams some extra money in order to encourage him to finish the work on time. Williams agreed to this, but later realized that the extra money wasn't as much as he had hoped for. He sued Roffey, saying that Roffey had promised to pay him more than he actually did.

The court had to decide whether Roffey was legally obligated to pay Williams more than the original agreed-upon amount. And the court said yes - even though there was no formal contract saying that Roffey would pay Williams more, the fact that Roffey had promised to do so was enough to make it legally binding.

Basically, the court said that if someone promises to pay you more money than they originally agreed to, and you rely on that promise to your own benefit, then they can't back out of it just because there's no formal contract. It's kind of like if someone promised to give you a cookie if you cleaned your room, and you cleaned your room expecting to get a cookie - they can't just change their mind later and say they don't want to give you the cookie anymore.