A Croydon man has been jailed for five years for his role in a spate of violent robberies on petrol stations and shops in the borough and throughout south-east London.

Sean Oyetunji, 19, of Beulah Hill, South Norwood, was one of five men sentenced to a total of 24 years for robbery, false imprisonment and conspiracy to rob at Kingston Crown Court last Thursday.

After the case police said they were unhappy with the sentences and it is thought they may appeal to have them extended.

Detective Chief Inspector Keith Butler said: "London is a far safer place as a result of this police operation leading to these men being locked up for some time.

"However, we are disappointed with the sentences and further legal advice is being taken."

Dennis Jerome James, 20, of Clarence Avenue, SW4, Courtney Adams, 19, from Tulse Hill, and Ivan Blackwood, 18, from Bromley, were also sentenced to five years.

Andrew Goldwin Banton, 18, from Stockwell, was sentenced to four years.

Between them the men admitted to being involved in 14 offences and five of the men including Oyetunji pleaded guilty when they appeared at Kingston Crown Court on September 29 last year.

The group carried out its first attack in January 2005 and used hammers, axes, meat cleavers and iron bars to threaten, attack and beat their victims.

The robberies included an attack on the Co-op Supermarket in Green Lane, Thornton Heath, on March 5, 2005, and another robbery on April 13, 2005, in Shirley.

The men forced their way into Tesco Express in Wickham Road at around 5am when staff were preparing to open for business.

They were threatened with a hammer and tied up while the gang stole contents from the safe as well as their personal property.

However, as part of a pre-planned surveillance operation, flying squad officers were waiting nearby and arrested the robbers as they attempted to escape in two cars.

Blackwood drove at police officers, knocking one of them over but all the men were soon arrested and the property recovered.

Operation Bonhill was set up by flying squad after officers linked a string of violent early morning robberies on staff at petrol stations and shops in south-east London.