The Hammers are among the leading candidates to take over the 80,000-seater venue and, unlike rival bidders Tottenham, are committed to retaining the running track.
The track is key to delivering the athletics legacy that London 2012 chiefs made a cornerstone of their successful campaign to stage the Games.
And Ed Warner, UKA’s chairman, revealed it was a major factor in their decision to endorse West Ham’s proposal, made in partnership with Newham Council, above all others.
“What has impressed me so much about the joint bid from West Ham and Newham is their clear commitment to the spirit of the Olympic legacy and not just athletics at the elite end, but with the retention of the community track, our future champions and club runners too,” said Warner.
Warner added that West Ham would support UKA’s attempts to host the athletics World Championship at the stadium in 2015.
West Ham vice-chairman Karren Brady called UKA’s support “a powerful and highly-valued testament” to their ability to realise the legacy pledge.