Convicted criminals have been spending their days drinking, smoking drugs and shopping while they are supposed to be paying for their crimes through community service.

The group has been at Windmill Park every Saturday since November last year to paint a fence. It is part of an unpaid work sentence handed to them by the courts.

But the painting has hardly been started and eyewitnesses said the offenders spend the day drinking cans of beer, smoking marijuana and visiting a nearby McDonald's.

A witness handed the photos to the Croydon Guardian this week after becoming so frustrated with observing what the group had been up to each week for the past six months.

The man, who did not want to be named, said: "They have been on this particular job since November and they are supposed to be painting the fence around the park but very little has been done. To be honest it just takes the mick out of me and all of the rest of the taxpayers who have to pay for muppets like this."

Another witness who has also been observing the antics of the "workers" said: "I work so hard in my job in Croydon and I am disgusted and devastated that my tax is being wasted on people who commit crimes and spend all day on community service drinking, smoking and shopping."

Unpaid work punishments are handed to people whose crimes have harmed a community, such as being drunk and disorderly, committing antisocial behaviour or criminal damage.

It may also be used for serious one-off offences such as high level drink-driving or driving while disqualified.

According to the Government, community sentences are not a "soft option" and that they "change offenders' behaviour".

It also claims that "unpaid work can also give offenders new skills and opportunities for practical learning in real situations which prepares them for employment or formal training".

The Croydon Guardian has passed the photos on to the the Probation Service and a spokesman said that it will now be investigating the matter.

He added: "We take supervision of offenders seriously. If we are provided with any evidence that offenders are not behaving appropriately we will investigate and take necessary action."