Prison officer cut hole in her trousers to have sex with inmate nicknamed 'Cocky'

Stephanie Smithwhite has been jailed for two years for her affair with Curtis 'Cocky' Warren. Photo / Supplied

A UK prison officer has been jailed after carrying out a six-month affair behind bars with a notorious drug smuggler.

The court also heard that the officer, 40-year-old Stephanie Smithwhite, cut a hole in her uniform trousers to facilitate sexual liaisons with imprisoned gangster Curtis 'Cocky' Warren.

Smithwhite denied that she cut the hole for a sexual purpose but the sentencing judge said it was hard to imagine why else she would make an incision there, Metro reports.

The pair met secretly in his cell, the kitchen and the laundry room at Frankland Prison, which is home to some of the UK's most dangerous prisoners.

Durham Crown Court also heard that Smithwhite sent Warren a photograph of herself wearing a catsuit.

She was caught out when fellow officers began to suspect her and began monitoring her inside the prison, catching her passing notes to Warren.

Smithwhite last month admitted two counts of misconduct in a public office.

Judge Jonathan Carroll said that Smithwhite was infatuated with Warren, who he described as a "major league offender" and who used the officer to smuggle in drugs and asked her about the prison security measures.

The smitten prison guard admitted to detectives that she was "devastated" by events but still hoped that there was a chance her relationship with Warren might continue.

Her lawyer argued that his client had made a "catastrophic error of judgment", adding that Smithwhite has "fallen in love with the wrong person".

"Your conduct represents the very most grave breach of trust placed in you," the judge told Smithwhite as he sentenced her to two years in jail.