When you want a package delivered in a short period of time, you want a courier service that offers an expedited courier service, such as same day or next day. Usually this type of service has a higher price, but there are times when you need to get your package to its destination quickly, so only this type of service will work.
Most UK courier companies provide an express service, and some of the larger and more established courier companies will provide an international express courier service so that you can receive your overseas delivery within a short period of time.
The reason express courier services are priced higher is due to a) demand and b) there may be external factors that mean certain limits must be met. In certain cases, the only way to get a delivery to its destination in such a short time would be to fly it, so there are additional costs involved.
Express Courier services often rely on third parties to help get the shipment to its destination. These third parties may involve airlines or shipping companies.
Many courier companies work closely with their customers, and in London you will see bicycle couriers zipping around the city. This is so they can beat the traffic and deliver your package on time. With bike couriers there are also fewer overheads, such as fuel and congestion charges, so the savings can be passed on to the customer. When a customer uses a courier company for repeat business, it is common for a good working relationship to be forged and discounts are often offered, especially for shorter deliveries. Repeat business is great for both the messenger and the customer.