Williams will need to win two fights to be crowned Elite Three Nations champion at 91kg. Ansell claimed the youth 48kg title in Scotland earlier this month.
England coach Amanda Coulson said: “Every boxer selected to compete will have been preparing really well towards representing England at this prestigious event.
“Each boxer will pick up international experience with an overall goal of being crowned the Elite GB Three Nations champion.”
If Williams is successful he will end the season as Great Britain’s number two, putting him in a strong position to challenge current number one Cheavon Clarke with Olympic qualification beginning next year.
Meanwhile, 17-year-old Leamington fighter Josh Finch will box former world champion Ricky Hatton’s son Cameron on Cleary’s Gym’s home show Friday June 8.
Tickets for the show can be purchased by calling Ady Bush on 07581 506820.