Partly it is general caution about security. Partly it is specific caution about another Gordon Brown “bigoted woman” moment. But it is all about caution.

Picture: David Cameron arrives on Thursday at the launch of the Scottish Conservative manifesto at the Emirates Arena.

Voters need to know that what is daily passed off as an election “campaign” at times feels like nothing more than an antiseptic exercise in keeping our party leaders away from real voters and real situations at all costs.

So I will tell you what these events are really like.

This morning the Prime Minister came to “Scotland” to launch the Scottish Tory manifesto.

This is what happened.

First, the warning sent the night before: the PM is coming to the Emirates Stadium in Glasgow’s East End but you cannot say that in advance. That’s in red ink.

The idea may well be rooted in genuine security concerns but the unfortunate by-product is that it all helps keep away any real voter who might try to come into contact with the PM. For that could be catastrophic in an election couldn’t it?

The stadium is cordoned off. It’s well away from any normal human life anyhow.

You are directed to a desk where they give you a plastic wristband to distinguish media from party supporters who don’t look like they’ve necessarily come from Parkhead.

You are escorted to a lift. Another official escorts you to a media room where you are corralled.

Then it is time. You are led to the media section in the hall where a seat says: “Reserved for Media”

I am media. I sit. Big mistake.

I am told I can’t sit. I tell them I am media and I am indeed sitting. I show the media wristband. They say I must move but won’t say why.

I refuse, telling them if they want to sling Channel 4 News out of a general election event then get on with it.

Because here’s the game. These seats are reserved for the known correspondents – the Scottish Tory Leader will call them all by first and surnames and organisation.

It is chummy. It is clubby. I doubt she knows my name. Doubt any party political leaders do and long may that remain so.

Because what is being passed off live and in edited sound bites is a pretend press conference. It is nothing of the sort – just the known names.

I have asked in advance politely to ask a question. The Tory press officers are primed.

Some questions are asked. The microphone never comes my way. Fascinatingly it is never given over to any of the names who do ask questions. The party press officer holds onto that microphone for dear life – not the journo.

This is what they once tried on at a government press conference in Beijing – the difference being in Communist China you can get away with holding the microphone. Not here it seems.

Perhaps they knew I would have grabbed it as any journo should for the follow-up question, given the near certainty that the party leader will not answer the question first time around.

This is standard protocol the world over. Not at this press conference. Not at this election. I checked with a friend and colleague covering this day in, day out. I was told they never actually give you the microphone. Ever – god no!

So I dangle my arm in the air like a numpty sensing what is about to happen. At 15 stone and 6’4″ in the front media row, no one managed to see me there.

Predictable horror and outrage when I try to ask David Cameron a question as he is hustled away from the hall by a combination of officials and close protection police officers.

And here’s the sting – I just wanted to him why he wasn’t doing a walkabout to meet voters in Glasgow outside this synthetic event.

“I’ll talk to you later,” said The Prime Minister as he was hustled away.

A press officer claiming to be from The Prime Minister’s office apologised several times after this nonsense was all over.

As I left the stadium one of the invited Conservative party guests there turned to the security guard:

“Can I get a train or bus from here to the city centre? I’m not from around here.”

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