Cyclist foils attempted robbery by crashing into thieves

A determined Polish cyclist has used his bike to mow down a pair of "dirty" would-be thieves after a brazen daylight bag snatching.

After assaulting a 17-year old girl on her way to school and stealing her purse, two female thieves, aged 19 and 23, attempted to flee through the city of Wroclaw, Poland.

Hearing the young teen's cries for help, a cyclist raced across a busy intersection and ran down the pair.

Handlebar footage of the incident was posted to Youtube on April 19, with the cyclist describing how the events unfolded.

"(I) could hear screaming... I knocked them down," the amateur crime buster wrote.

The cyclist described the two thieves as "dirty, sloppy, with many scares at their hands."

The women screamed "f--k off, if you touch me I'll bite you" before police eventually arrived, said the cyclist.

Citizen's arrests are legal in Poland when there's high probability a criminal will escape.

The two women are believed to be in police custody.