A clampdown on street robberies in Oxford has been extended for two more months after being hailed a big success.

Almost 80 arrests have been made since April 14, when extra officers were drafted in as part of Operation Robbery, Thames Valley Police's crackdown on street crime.

The extra manpower was expected to be available for six weeks -- but top officers have extended it because of the successes in removing robbers from the streets.

Traffic police, mounted officers, the dog section and tactical support officers, who man armed response vehicles, have been on duty to boost Oxford police's efforts.

This has resulted in a 36 per cent drop in robbery between April 14 and May 26, compared with the same period in 2002.

Officers have arrested 79 offenders and questioned 198 in just six weeks. The extra officers will be in the city until the beginning of August.

Last summer, overseas students studying at Oxford's language schools were targeted by offenders across the city. Police were concerned the high student population and influx of tourists could prove rich pickings for street robbers this summer.

Jane Baker, a director of The Lake School of English, in Park End Street, said: "I welcome anything that can be done to protect students from petty theft and crime."

The teams are also targeting burglary and car crime to tackle offences linked to about two thirds of Oxford's drug problem.

Det Ch Insp Steve Thwaites, heading Operation Robbery, said the extra manpower would be reviewed at the start of August and could be extended again.

He said: "It would be foolish to suggest we've got every single robber. There are more out there and it's a question of time before we get them."