Norfolk Police let a gang of travellers go on the rampage because they failed to grasp the “community tensions”, leaving a seaside town in lockdown, a review has found.

Shops, bars and restaurants were forced to close on one of the busiest weekends of the year after 23 motorhomes parked up during Cromer’s August carnival this year.

In total, 37 crimes were reported to police including a rape, threatening behaviour and thefts. One pub landlord was pulled over the counter as some of the travellers demanded money. Meanwhile, an Indian restaurant was “ambushed” as around 40 people stormed in stealing alcohol and upsetting diners.

According to the force’s internal review published yesterday, the failure of commanders to recognise the tensions in the town meant they sent too few officer leaving those on the ground tackling the problem in an “impossible situation”.

In total, three people have been arrested in connection with the rape, but no one else has been arrested or convicted for any other crimes that weekend.

Because the constabulary wrongly assessed events in isolation they even posted a message on social media stating that the anti-social behaviour was “low level”.

Norfolk Police had been told by Suffolk Police that the group of travellers had left Lowestoft after causing some disruption there and were heading to Norfolk, the report said.