Watson Phillips Norman will be responsible for targeting 250,000 people in The National Trust's UK supporter database with mailer packs that will draw attention to areas of the country that are susceptible to sea level rise, coastal erosion, pollution and inappropriate development.
The Neptune Coastline Campaign, which first launched in 1965, has so far raised more than £45m for the protection of more than 700 miles of UK coastline.
The National Trust said this year's campaign coincided with the second anniversary of the Boscastle floods in Cornwall, which caused millions of pounds worth of damage.
The mail outs will contain additional information on the work of The National Trust and how readers can become more involved.
Gail Cookson, client services manager at Watson Phillips Norman, said: "[We] have created a limited-edition map as the centrepiece of the mailing, which highlights some of the places in England, Wales and Northern Ireland that are currently at risk.
"We felt it was important to show potential donors where there money is likely to be spent thus providing a real and tangible connection with the Trust's valuable work."
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