Inside the Vatican: Behind the scenes at the 'chaotic' Rome institution

When Pope Benedict XVI announced his resignation last month, the decision sent shock waves through the Catholic community and around the world.

The announcement was so unprecedented it even took journalist John Thavis, who has reported on the inner workings of the Vatican for three decades, by surprise.

Pope Benedict's retirement brought the Vatican to the forefront of the news for weeks, as millions tried to work out what the Catholic Church would do next.

Thavis, whose new book 'The Vatican Diaries' gives a behind-the-scenes look at the Rome institution, said he was 'as shocked as anyone' by Benedict's resignation.

Thavis, who worked for the Catholic News Service as Rome Bureau Chief from 1983 until last year, told Yahoo!: "He looked prepared for it, but it's still a shock when you actually hear him say it."

Describing his book, Thavis added: "I wanted to bring the context, the flavour and the humanisation of this place. To understand the Vatican you have to understand that.”

The papal conclave will sit soon in Rome to vote for the next pontiff. Cardinals will vote in secret in the Sistine Chapel, before burning their ballots.

When the conclave have not reached a decision, black smoke comes from the Sistine Chapel's famous chimney. When they have elected a new Pope, chemicals are added to turn the smoke white, and thousands outside know an appointment is imminent.

In contrast to the smooth-running, highly-choreographed organisation seen from the outside, Thavis says the Vatican is frequently a place where 'things go off the rails'.

Thavis said he learned quite early on in his reporting career at the Vatican that there was little cross-communication between different departments.

He explains how, after interviewing officials, he would be questioned himself so they could find out 'what other Vatican departments are doing'.

Explaining the lack of inner communication, he says: "The left hand often doesn't know what the right hand is doing at the Vatican, and it's often a lot more decentralised than people think.

"Much of what happens at the Vatican is, in a sense, theatre. The conclave is a classic example.

"I wanted to give a glimpse of this backstage reality and how it is different to the caricature people associate with the Vatican."

Related: Conclave to elect new Pope begins on Tuesday

His best example of the 'backstage reality' comes when he recalls the papal conclave in 2005, when Benedict XVI began his papacy.

A somewhat farcical conclave saw smoke accidentally released inside the chapel, a communication meltdown, and organisational chaos.

It began when the cardinals had trouble lighting the stove, leading to smoke billowing back into the Sistine Chapel and scenes which, according to what insiders told Thavis afterwards, looked like 'men gathered around a barbecue, debating the finer points of cooking with charcoal'.

Even when the stove was lit and the announcement could be made, the white smoke did not emerge in time with the ringing of the giant 'campanone' bell at St Peter's.

The resulting chaos saw Vatican officials frantically trying to reach the bell ringer by mobile phone to co-ordinate the two events.

Unfortunately, since the Vatican had installed a jamming device in the Sistine Chapel preventing electronic eavesdropping, they had no way of reaching him.

Thousands waiting in St Peter's Square, meanwhile, were completely oblivious to the frantic goings-on inside.

He said: "The Vatican is seen as this monolithic power struggle and a classic heirachy where orders come down from on high and are carried out immediately by everyone marching in step."

But the reality inside the Vatican is often a different experience.

Thavis says Benedict will be remembered as a 'misunderstood' pontiff who 'had a hard time promoting his religious message through the mass media'.

Part of this, Thavis says, is because officials spent more time rephrasing Benedict's comments than with any other Pope.

The Vatican Diaries tells how, on one papal trip, one official rewrote one of Benedict's public statements, and would justify this process on the premise of 'cleaning up' the Pope's slightly broken Italian.

He may have covered the intricacies of Benedict XVI's eight-year papacy, but Thavis insists even he was taken aback when the Pope announced his resignation in February.

He added: "He had mentioned the idea of retiring a year ago. I looked at his calendar I knew he didn't have much on.

"Even so, it's one thing to think about him retiring, but another to actually hear him say it.

"I think he realised it would take a younger, more energetic man to deal with the problems inside the Vatican."