Sections of the M25 form part of two long-distance E-roads, designated by the United Nations Economic Commission for Europe. The E15, which runs from Inverness to Algeciras, follows the M25 and A282 clockwise from the A1(M) at junction 23 to the M20 at junction 3; while the E30 Cork to Omsk route runs from the M4 at junction 15, clockwise to the A12 at junction 28. The United Kingdom is formally part of the E-roads network but, unlike in other countries, these routes are not marked on any road signs.
Sections of the M25 form part of two long-distance E-roads, designated by the United Nations Economic Commission for Europe. The E15, which runs from Inverness to Algeciras, follows the M25 and A282 clockwise from the A1(M) at junction 23 to the M20 at junction 3; while the E30 Cork to Omsk route runs from the M4 at junction 15, clockwise to the A12 at junction 28. The United Kingdom is formally part of the E-roads network but, unlike in other countries, these routes are not marked on any road signs.