I was doing about 70mph.
The quality of the footage is good considering it's a cheap entry-level mobile phone, no substitute for a proper dash cam mind. Encodes in MP4 format so the size is kept down and I've got 10Gb free on the 16Gb micro SD card after apps and music.
You can get proper (free) apps to turn your mobile into a dash cam complete with GPS. I did try a coupe and noticed there is a delay in the app recording the speed via the GPS chip - the app would claim I was doing 30mph when I was stationary - again, low-spec phone.