Any house extension or improvement project completed in the capital within the last two years is eligible for Don't Move, Improve!
Organised annually by New London Architecture (NLA), the contest champions "emerging trends, imaginative design and original problem-solving".
This year's contest will be judged by a panel of architects and industry experts, including NLA chairman Peter Murray, Dezeen editor Amy Frearson, architect Carl Turner and Ash Sakula co-founder Cany Ash.
Last year's overall winner was a garden room containing a sunken Japanese-style bath. Other lauded projects included a project featuring a lookout post clad in wooden shingles and a garden studio dedicated to rug making.
Submissions are open until Friday 27 October 2017 and winners will be announced at a ceremony in the new year.
Successful projects will feature in a major exhibition and magazine, and all featured practices will be invited to participate in NLA's popular Design Surgeries – giving them an opportunity to meet potential clients.
For more information, visit the NLA website.