There are two shocking aspects to the case of the London handyman who tried to frame his school caretaker boss  using planted child porn images. First, that it happened at all, second, that it took four years of hell for the accused to sort out when computer forensics clearly suggested something odd had happened.

There should be a simpler way for people to protect themselves against almost trivial digital crimes but as yet none exists.

The facts of the case: A judge at the Old Bailey yesterday jailed Neil Weiner for 12 years for placing 177 mostly 'level 4' severity child abuse images on the laptop of Eddie Thompson, caretaker of Swanlea Secondary School in East London in 2006.

The court heard that Weiner had broken the password for his boss's laptop after shoulder-surfing him, transferring images to the machine after changing file stamps to make it appear that they had been downloaded over a period of time.

He then informed on his boss under a false name and sent police a disc containing what he claimed were copies of the images. Weiner also tipped off a sensation-hungry local newspaper after his boss had been arrested and released on bail in early 2007, which turned the innocent Thompson into a social pariah.

Weiner’s motivation for the campaign was the usual mixture of stupid spite and the possibility of perhaps getting his boss’s job.

Luckily, Weiner made a number of important technical mistakes, which allowed police to help unravel the plot using computer forensics, including that the images sent to them on disc did not match the file stamps of the laptop versions.

They were also able to work out that the files had been transferred to the laptop in 31 seconds from external media and could not therefore have been downloaded from the Internet regardless of what the time stamps on them said.

When somebody is accused of possessing illegal images, forensics should be the first line of evidence. How did these images get on to the accused’s PC and does that fit with the accusation being made?

"What he did was so stupid and unnecessary. It makes me sad because what he tried to do to me is the very thing he ended up doing to himself," said Thompson of the man behind the plot, which is a generous comment in the circumstances.

The on unsettling aspect of the case is that a more expert computer user might have been able to overcome some of the forensic hurdles that helped give away the plot.

The digital world put an innocent man through four years if suffering but it should also have been able to save him sooner than it did. Perhaps it is time for security software that protects users more effectively at this basic level, logging access, file transfers and other activity.

It shouldn't take a police forensics department to head off a digital crime so simple even a school handyman was able to give it a go.