During this years' campaign, a 20-foot-tall man made of poppies will appear close to the check-in desks in Terminal 5 in preparation for an awareness-raising event due to take place on Remembrance Day.
At 11am on November 11, as the annual two-minute silence takes place, the digital advertising screens throughout the terminal will show poppies in a virtual "poppy drop".
The Gate has also created a viral "Popp-E" email signature which can be downloaded from the Poppy Appeal website.
The signature shows an image of a poppy with a link back to the website so that anyone who receives a message containing the signature can download their own version.
Those downloading the signature can make a voluntary donation, with both corporate and individual versions of the signature available.
The campaign also includes animated digital cross-track projection posters at tube and overground stations in central London including Euston, Bond Street, Victoria and Piccadily Circus.
The posters show the image of an injured veteran alone in a wheelchair in a sunny park. Gradually individual poppies float into the image and come to form Poppy Man who gently rests his hands on the man's shoulders.
Text appears in the ad saying: "Remember 900,000 ex-service people injured in action" followed by "Don't forget your poppy."
The Poppy Man character, which was developed by The Gate in 2007, will also appear in a series of posters across England and Wales where he is shown supporting people who have been helped by the Legion.
All of the posters include an SMS shortcode for instant donations by text message.
Versions of the Poppy Man posters will also run on more than 100 Nationwide cash point machines for the duration of the campaign.
Customers will see the posters appear as they use the cash machines and when the transaction is completed, the line "Don't forget your poppy" will appear on the screen.
Russell Thompson, director of national events and fundraising at the Royal British Legion, said: "The Poppy Man character that The Gate has developed provides a really powerful symbol of the work that we do, and the impact that individuals buying and wearing their poppy can have for those who need our help.
"This year, alongside the posters, we've taken Poppy Man in new directions and into new spaces. The digital posters and the viral email signature that the agency has produced attract a younger generation to support the Legion as well as emphasising our key values."
Matt Leach, media planning director at The Gate, said: "We have designed a campaign that makes the most of each of the environments in which our audience will engage, in close proximity to our Poppy People who collect donations and distribute the famous poppies."