Shopkeepers in Lincoln have been warned to tighten security while police hunt the culprits behind a string of knifepoint robberies.

There have been six knifepoint robberies in the Lincoln area in the last month, sparking a major police investigation.

Officers are intensifying efforts to track down those responsible for the robberies – all of which have been carried out in and around Lincoln.

But in an exclusive interview with the Echo, Detective Inspector Katrina Morton said local businesses needed to tighten security while the suspects continued to evade the police.

Asked if another such robbery could happen again in the area, she said: "quite possibly".

"The question is, is there more than one person doing this?" she said.

"We have in place response plans.

"I am hoping that we don't have another incident."

The spate of knifepoint robberies began on Wednesday, November 18 at Brant Road's Betfred.

The suspect was wearing a balaclava and hoodie, and he threatened staff with a knife before taking cash.

There were further robberies that month at Starbucks on Tritton Road and The Oasis on Newark Road.

There have been another three incidents in Lincoln and Washingborough this month – all of them knifepoint robberies.

Anyone with information that could help the police should ring (01522) 882222.

Alternatively, ring the charity Crimestoppers anonymously on 0800 555 111.