I've done some research into all this.
A thread that might be worth reading is:
http://forums.overclockers.co.uk/showthread.php?t=17910453
After doing some further research I found the following clauses that maybe of interest to you.
(ii) Exception.-Clause (i)(I) shall not apply to an alien who committed only one crime if-
(I) the crime was committed when the alien was under 18 years of age, and the crime was committed (and the alien released from any confinement to a prison or correctional institution imposed for the crime) more than 5 years before the date of application for a visa or other documentation and the date of application for admission to the United States, or
(II) the maximum penalty possible for the crime of which the alien was convicted (or which the alien admits having committed or of which the acts that the alien admits having committed constituted the essential elements) did not exceed imprisonment for one year and, if the alien was convicted of such crime, the alien was not sentenced to a term of imprisonment in excess of 6 months (regardless of the extent to which the sentence was ultimately executed).
(B) Multiple criminal convictions.-Any alien convicted of 2 or more offenses (other than purely political offenses), regardless of whether the conviction was in a single trial or whether the offenses arose from a single scheme of misconduct and regardless of whether the offenses involved moral turpitude, for which the aggregate sentences to confinement 2/ were 5 years or more is inadmissible.
As already said, the US have no access to UK criminal records.
Unless they have intelligence on you (usually terrorism or drugs) then you should just sail through without a single hitch.
