This article is about the former, duplicate A407 in Bristol.
For the current A407 in London, see A407
First re-discovered, almost by accident on an old home movie showing a sign at J1 on the M32, the use of the A407 number in Bristol has since been confirmed by a 1970s or 80s 1:2500 Ordnance Survey sheet. On this map, the A4174 is already marked as approaching the junction from the west, with the A407 continuing east on the line of what is now the A4174 through the Hambrook junction. At the current site of the Bromley Heath Roundabout it turns south onto the A4017, itself formerly a spur of the A4174. Sadly at this point the sheets change, and no further trace of the A407 is found, although we can suppose that it continued south on the A4017 route to meet the A432 in Downend. Whether or not there was the fork that exists today is unclear.