Six South West Trains employees have been jailed for nearly seven years after a ticketing fraud thought to be worth more than £100,000.

The three men and three women, who all worked as ticket office clerks at Richmond station, committed the fraud between October 2011 and January 2013.

The group comprised Linus Okrah, 45, from Wanstead, David Rudland, 67, from Epsom, Julia Cann, 33, from Brentford, Alicia Dunn, 34, from Luton, Grace Oyegoke, 33, from Greenhithe, and Olufisayo Dada, 35, from Brixton.

Richmond and Twickenham Times: Linus Okrah: 18 months insideLinus Okrah: 18 months inside

The crime came to light after South West Trains asked British Transport Police (BTP) to investigate an anomaly in their accounting system in October 2012.

The investigation revealed the problem centred around Richmond station and a further investigation revealed members of staff had been defrauding the ticket and Oyster card system.

The staff illegally sold fraudulent cards to unsuspecting customers and pocketed the money in a move prosecutors described as a "sell one get one free" scam.

The fraudsters were arrested in January 2013 after further evidence came to light they had been taking advantage of the till systems to create and use illicit travel cards, which were found at their home addresses.

Police believe the Oyster card fraud was about £68,000 and an exact figure could not be placed on the travel card fraud, but the court heard it would run into tens of thousands of pounds.

All six employees were found guilty of conspiracy to commit fraud and were sentenced at Kingston Crown Court on Thursday, September 4.

Okrah was jailed for 18 months, Rudland was sentenced to 13 months and Cann and Dunn were both jailed for nine months.

Oyegoke was sentenced to nine months, suspended for two years, told to do 150 hours of unpaid work, to be completed in 12 months, and ordered to wear an electronic tag for three months.

Richmond and Twickenham Times: Dada: 18 months plus six monthsDada: 18 months plus six months

Dada was sentenced to 18 months for conspiracy to commit fraud and another six months, to run consecutively, after pleading guilty to possessing false identity documents with intent.

Detective Constable Becci Crampton said: "Between them, these people had more than 50 years service with South West Trains, yet they chose to throw that away for the sake of greed.

"Throughout their trial, they denied any responsibility for the fraud, claiming the irregularities had been caused by technical faults with ticket machines.

"I am satisfied with the sentences handed down, and hope those involved will use their sentences to reflect on what they have done."