The practice, tipped by Building to win the high-profile job last month, was named by project developer Lee Valley Park Authority when the site was confirmed as the venue for the 2005 World Athletics Championship last Thursday.
The decision to name the architect followed Wembley chief Sir Rodney Walker's announcement that the new stadium would not be able to host the 2005 athletics championship.
FaulknerBrowns beat off Arup Associates, Miller Partnership, Burland TM, Building Design Partnership and Ward McHugh Associates to win the job.
The design team for the 43 000-seater stadium, warm-up track and associated facilities includes TTH Stadium Consultants, structural engineer Anthony Hunt Associates and BDP Environmental Services.
UK Athletics chief executive David Moorcroft said the scheme could now push ahead. He said: "It was right to revisit Wembley one more time, but Picketts Lock was always our first choice. We must now all work together to deliver the facilities for the 2005 championships and a permanent legacy for athletics." The uncertainty over the venue for the championship prevented the stadium's sponsors, UK Athletics and Lee Valley Regional Park Authority, from seeking commercial backers.
UK Athletics is now understood to be looking for commercial backing for Picketts Lock, which has £72m confirmed funding so far. Final costings will be decided when the design is completed.
Proposals for extra funding include finding a commercial sponsor for a health and fitness centre. Other facilities will include a 200 m indoor track.
A planning application is due to be submitted in May. Consultation on the transport, environmental and design elements will take place in March.
Sir Rodney, chairman of Wembley National Stadium Limited, is due to go back to the City to fund the £326.5m scheme in April.
A source said the stadium could still be designed so that it could host athletics events, as a temporary deck could be installed over the football pitch to carry a track. This would be removed when not required. The athletics deck would take six months to install.
