Research

For the other outdoor medium of promotion, I have decided to create a phonebox advert. 
This is the information I found on www.clearchannel.co.uk

Situated in prime urban locations across the UK, our Connect phoneboxes reach people while they are out and about and as purchasing decisions are being made.

Our Connect phoneboxes are situated in key London areas such as Westminister (222 panels in an area with notoriously few advertising opportunities), Camden, Southwark, Kensington and Chelsea, and many more. Our national Connect packs also offer advertisers a strong presence in major national cities including Leeds, Newcastle and Glasgow.

Features

• Connect is highly cost-effective, flexible and targeted, offering affordable value for businesses of all sizes.
• We are flexible in terms of campaign size; you can handpick as many sites as you need. Panels will be sold on a bespoke level and are ideal for long-term bookings in the area that is right for you. 
• All panels are head-on to reach a high volume of traffic and pedestrians with maximum impact.
• Connect panels can be purchased as part of a proximity campaign. Panels are within feet of local businesses and can be directional as well as showcasing your brand.
• All sites are barcoded for proof-of-posting, providing an auto-tracking system to ensure campaign delivery is 100% accountable.

These are some images I found on google: