Mr Lewis, 28, co-founded Ravel Law, taking on LexisNexis, to help law firms and law schools research cases more efficiently. 'After only two years in the market', says Forbes, the business's services were in use at half the top law firms and law schools. Vikrum Aiyer, 29, deputy chief of staff at the US Commerce Department, is the second on the list.

Few in practice

R David Edelman, formerly policy adviser in the State Department's Office of Cyber Affairs and now director at the National Security Council, also features on the list - as does Jay Greenberg, founder of LexShares. Forbes says: 'Relatively few of this year’s honorees are actually using their law degrees to practice law'. Source: Forbes