Merseyside's top prosecutor issued a New Year warning urging people to use social media responsibly, especially when involved in court cases - or risk a prison term. Paul Whittaker, Chief Crown Prosecutor of CPS Mersey-Cheshire, said: "Last year we saw more and more instances of people using social media in a way which had the potential to undermine prosecutions or even put them at risk of prosecution. "For example, a number of people have been jailed after using media such as Facebook in a criminal way, or to encourage criminal behaviour." Mr Whittaker highlighted the cases of Jordon Blackshaw and Perry Sutcliffe-Keenan who were both jailed for four years for inciting riots via Facebook during the nationwide civil unrest in August. "The cases of Blackshaw and Sutcliffe-Keenan highlights the potential dangers of misuse of social media. Both of these young men ultimately paid with their liberty. "Illegal on-line activity does not have to relate to riots - it can be any encouragement to carry out any criminal act. "What many people may not realise is that posting information on social media means that the information is in the public domain and can be viewed by anyone. This can expose the user to arrest and prosecution if their activity breaks the law, such as if it involves racist abuse. Many people do not seem to appreciate this. "The irony is that the person will have effectively handed police and prosecutors the evidence to build a case against them." Mr Whittaker also warned those involved in prosecutions to avoid the temptation to use social media to become a digital detective or virtual judge and jury. "We've seen instances of people conducting makeshift Facebook I.D. parades and searching for suspects on-line. People have also posted comments about ongoing court cases which can have very serious implications if prosecutions are still running. "If people don't stop and think, it's only a matter of time before a case collapses because of careless comments on-line which would be devastating for us and, more importantly, for any victim involved. "I urge people to resolve to let investigators and prosecutors do their job this year and resist the temptation to become virtual vigilantes."