On Saturday, March 3, between 5am and 5.15am, the cab driver picked up a man from Broad Street, Banbury who asked to be taken to Daventry.
When they arrived at Collingwood Way, Southbrook, the man threatened the driver with a knife and demanded cash.
The robber is described as a white man in his mid-20s, about 5ft 9in and of slim build.
He had dark hair, was clean shaven with a square jaw and was wearing a black jacket, light- coloured trousers and white trainers. He was also carrying two holdalls.
M40 closure in south Warwickshire is expected to cause delays on the edge of Banbury
Fairport wraps up a fantastic, sun-soaked Cropredy after 17,000 come to Banburyshire for the UK's most peaceful festival
Fire at Hook Norton destroys a number of sheds - firefighters renew appeals for care in dry weather
Crowds get acclimatised as Cropredy festival heats up and the music is scorching
Man seriously injured in crash near Banbury - Police make witness appeal. Warwickshire man arrested
Police officers are looking to speak to the two men pictured in these E-FITs as they believe they may have information about what happened.
Witnesses, or anyone who recognises the men in the E-FITs, are asked to contact Northamptonshire Police on 101. Alternatively, they can call Crimestoppers anonymously on 0800 555111.