In decades gone by, media people used to refer to The Green Ink brigade, letters often written by Angry of Tunbridge Wells, sometimes on lined paper and, for no good reason, in green ink. They usually went into the bin unopened since recipients knew they came from loonies.

These days, thanks to social media where anybody can have a voice, they have taken on greater significance. Whether comments below features or Facebook, You Tube or Twitter posts, they can't be spotted by the colour of the ink, though many still have interesting spellings and a predominance of capital letters.

My friend Stephen Fry and I had a discussion, after Twitter started, about the service. He loved it. I called it "a weapon of the Devil". He replied that at last it "gave people a voice". I answered that many did not deserve to have their voices heard.

My recent article in The Spectator about Edward Heath prompted much comment. Many of the online writers, not appreciating the irony, protested that this era of free speech, giving them the benefit of attention, should not apply to all people, specifically those they felt were not suitable to express opinions.

My personal favourites actually came from those normally assumed to be intelligent members of the media. The Editor of an online conspiracy theory site implied on Twitter that my contribution was an example of the Establishment protecting its own. The first time I've ever been described as a member of the Establishment - apart from that wonderful satirical club I joined as a teenager in the 60s, started by my friend Peter Cook. The Establishment was no help to me 15 years ago when I was prosecuted for crimes that had never taken place.

Camilla Long, famed Sunday Times interviewer, tweeted that forming an opinion about someone after talking to them for a couple of hours, was "insane".

Jon Niven, an excellent novelist, used my article as an excuse to wonder why every other pop star from the era had not been in the dock beside me. A reasonable question, especially if your books are based on the assumption that many in that decade were perverts, but avoiding the more interesting problems of judging the behaviour of another time by the morality of today. And of believing that time does not alter the accuracy of memories.

Of course The Spectator was partly to blame, initially putting a rather tabloid headline above the piece, but anybody bothering to read the entire essay must have noticed that a humorous commentary about a bisexual man talking to a celebrated ex Prime Minister in an era when being gay was illegal, and coming to the conclusion that he was asexual, was hardly a shocking revelation, but merely an interesting personal observation relating to the current moral panic. Or is that asking a lot of the current attention span and depth of understanding of many?

The Green Ink Brigade will, of course, never be sane or sensible analysts of any topic they deign to consider. But what is worrying in this century is the fact that many take them seriously. Just as the fact that now simple allegations are regarded as evidence in some courts of law is a devastating development for some of the innocent men and women languishing, at great expense to the tax payer, in Her Majesty's prisons. And for the reputations of some dead people who, possibly, deserve more from those of us left behind.

The reason that allegations of guilt are, these days, regarded as sacrosanct whereas allegations of innocence are mocked and spurned is, of course, easy to understand. They are far better stories.