Intersections:

• A5025 at Valley
• A4080 at Bryngwran
• A5114 at Llangefni
• A5025 at Llanfairpwllgwyngyll
• A4080 at Llanfairpwllgwyngyll
• A487 at Penrhos-garnedd
• A4087 at Penrhos-garnedd
• A4086 at Capel Curig
• A470 at Betws-y-Coed
• A543 at Pentrefoelas
• A494 at Druid
• A494 at Tyn-y-cefn
• A539 at Llangollen
• A483 at Chirk
• A495 at Oswestry
• A483 at Oswestry
• A458 at Shrewsbury
• A49 at Shrewsbury
• A458 at Shrewsbury
• A49 at Shrewsbury
• M54 Junction 7
• M54 Junction 5
• A442 at Telford
• A41 in Shropshire
• A449 at Gailey
• M6 Junction 12
• A460 at Cannock
• A34/A460 at Cannock
• A452 at Brownhills
• A461 at Hammerwich
• A38 at Shenstone
• A38 at Weeford
• A453 at Bonehill
• A51 at Tamworth
• M42 Junction 10
• A444 at Caldecote
• M69 Junction 1
• A4303 at Lutterworth
• M1 Junction 18
• A45 at Weedon Bec
• A43 at Towcester
• A508 at Old Stratford
• A422 at Milton Keynes
• A509 at Milton Keynes
• A421 at Milton Keynes
• A4146 at Simpson
• A4146 at Fenny Stratford
• A4012 at Hockliffe
• A505 at Houghton Regis
• A5120 at Houghton Regis
• A505 at Dunstable
• M1 Junction 9 at Flamstead
• A410 at London
• A5150 at London
• A4006 at London
• A504 at London
• A406 at London
• A407 at London
• A4003 at London
• A41 at London
• A501 at London
• A4205 at London
• A4209 at London

The GSM encryption algorithm, A5, is closed and weak stream cipher. It's made by french and is designed to be unsecure with its 40bit strength. It is used in most, but not all GSM networks.