As any social media practitioner will tell you, inviting the public to provide content isn’t always wise – they might not say what you want them to.

Sadly, no-one remembered to tell London Assembly member Brian Coleman whose noble foray into social networking has already backfired badly.

On 24 April, the Conservative member for Barnet and Camden launched an online site on which the public could register their support for the police. Speaking as his Commend a Copper page was opened on Facebook, Coleman said: “The police do a very difficult job and get little thanks for it – even from areas where they should expect it. So I’ve decided to launch this site on Facebook so that anyone who thinks the police are doing a good job can stand up and say so.”

Of course, it also meant that anyone who thinks that the police – or Coleman himself – are doing a bad job could stand up and say so too.

Within hours, cheeky users were doing just that, with one user describing the police as “racist mason thugs with no morals who think the public are all terrorists.” Others cited the officers who struck Ian Tomlinson and Nicky Fisher at the recent demonstrations in London, as well as PC Rob Ward who talked on his Facebook page of his intention to "bash some long haired hippies" at the G20 protest.

Some responses were more personal. “Hey Brian, how much have you claimed on expenses for setting up this shoddy little attempt at PR?” said one.

Another user did commend a police officer though: “I'd like to commend the copper who caught Assembly Member Brian Coleman exceeding a 30mph speed limit in Borehamwood in January 2006. He already had 9 points on his driving licence. On 9 August 2006 at St Albans Magistrates' Court, Coleman was given three points on his licence, banned from driving for six months and fined £300. Although since then of course, he's run up famously large taxi bills at your and my expense.”

That prompted one user to suggest an alternative page: Commend a Cabbie, dedicated to “the cabbie or cabbies who managed to get over £8,000 in taxi fares out of the GLA via Mr Coleman for 07/08”.

Ouch.