A crackdown on bike thefts in Norwich has helped lead to a reduction in the number of incidents in the city with several arrests in its first month.

Operation Boneshaker was launched by Norfolk Police after an increase in thefts saw more than 300 stolen in Norwich since April.

Officers from the City Centre and West Centre Safer Neighbourhood Teams stopped several cyclists in the city as part of the operation, offering crime prevention advice and in some cases checking for proof of ownership.

Between July 8-14 police received 30 reports of bike theft, but that fell to 10 between the same dates this month.

Several arrests have been made as part of the campaign with two Norwich men sentenced at magistrates' court on Monday after pleading guilty to two counts of theft each.

A 29-year-old man who admitted stealing two bikes worth �400 each was given a 12-month community order and ordered to pay �200 in compensation. He also asked the court to take six similar offences into consideration.

A 37-year-old man who admitted stealing two bikes and asked for six similar offences to be taken into consideration was issued with a 12-month community order and ordered to pay �200 in compensation.

Inspector Chris Brooks said: 'The operation has led to a reduction in thefts and some good arrests. We've raised awareness around cycle security and the message seems to be getting through. We are still seeing some owners leave expensive bikes – some worth more than �400 – unlocked. You wouldn't leave that amount of cash lying around so why leave a bike?'

Officers will be holding a free cycle marking event outside The Forum on Saturday, August 27 between 10am-noon.

They are also appealing for help in tracing the owners of four recovered bikes.

•Rourke racing bike – bespoke handmade metallic red cycle with Mavic Kysrium wheels worth about �3,700. The bike was stolen from a garage on Newmarket Road around July 22-24.

•Hood Guru mountain bike – 20inch black frame with distinctive red shark mouth/teeth stickers near the handle bars. The bike was stolen from Pilling Park on June 21.

•Rooster Big Daddy BMX – luminous green bike, has a Norwich City Football Club sticker on the front of the handlebars and was stolen from the front garden of an address in Deloney Road on July 1.

•Trek 6000 mountain bike – black frame with white logos on front suspension. Stolen from the back garden of an address on Heigham Street on July 27.