The mailing will ask 30,000 Save the Children supporters to sign their name on a white band enclosed in the pack and return it to the charity so the signatures can be taken to the G8 Rally on July 2 in Edinburgh.
THe mailer says: "This time we're not asking you to put your hand in your pocket." The inner line reads: "We're asking you to put it in the air." The mailer shows a photograph of a hand in the air with a white wristband with the words "Make Poverty History" on it.
Proximity London has worked with Save the Children since its appointment in 2003.
Separately, Proximity London has promoted senior designer David Farley to the newly created role of head of design at the agency.
Previously, Farley worked as senior designer at Clarke Hooper Momentum before it was merged with Proximity in 2001. He has worked on a number of high-profile brand identity projects for clients including Shell, Virgin and Yell.
His role will be to oversee all brand design and ensure design central to the agency's creative output.
Caitlin Ryan, creative director at Proximity London, said: "I have no doubt that with a strong team to support him, Dave will make sure that design grows as an integral part of our creative process but also as a standalone discipline within the agency."
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