Final answer:
The ratio in Glasbrook v Glamorgan is a legal precedent from an English contract law case where the court decided that a legally binding contract was formed when a party agreed to pay for additional services beyond public duty provided by the police.
Step-by-step explanation:
The ratio in Glasbrook v Glamorgan relates to a legal case concerning principles in English contract law, focusing on the issue of whether an agreement to provide a service that one is already legally bound to provide can create a legally binding contract when additional payment is offered. In this case, Glasbrook Bros Ltd requested extra police protection during a miners' strike beyond what the police considered necessary. The court held that the police had provided a service exceeding their public duty at the request of Glasbrook Bros, who were therefore required to pay for the additional services as agreed.