By Daniel Sandford
BBC News, Florence, Italy
On the fourth floor of Florence's imposing Renaissance police headquarters, known as the Questura, there is a wide corridor.
Half of Italy's citizens have had their calls tapped at some point
Four doors lead off it into almost identical rooms, and inside each there are up to a dozen police officers.
All day they sit at computer consoles, wearing headphones, monitoring the phone calls of thousands of Italian citizens.
That is the scene in just one police headquarters, in one city.
They are not shy about it. Newsnight asked to film the telephone interception work, and they were more than happy to accommodate us.
In Italy, the state listens in to its citizens' phone calls. It is accepted, it is just how things are.
When the Rome-based think-tank Eurispes looked into the phenomenon, it estimated that during the last 10 years 30 million Italians had had their phone calls monitored.
That is because when the state taps someone's phone, it is not just listening in to the suspect. It is also listening in to everyone they talk to as well.
This is not something left over from Italy's violent 1970s and 1980s and the Cold War, and on the wane. It is increasing.
In the last five years, the number of phone taps has more then doubled. It is costing a fortune - 1bn euros (£688m) over the same five years.
The latest official figures for the UK are that in December 2003 there were 746 intercepts in place, and over the next year a further 1,983 were approved.
Italian police say they have foiled terror plots by monitoring calls
Obviously some will also have lapsed during that period; and those figures include intercepted mail as well as telephone calls.
There is a huge gulf between the extent of phone-tapping in the two countries.
The justification in Italy is that, faced with the twin threats of terrorism and the Mafia, the authorities would be crazy not to use telephone intercepts.
It is an argument that is worth sober consideration. Are we in Britain being too prudish about using a weapon that can be very effective?
After all, the Italian police still need the permission of a judge to set up an intercept.
But when you dig beneath the surface senior judges, who are very much in favour of phone-tapping, concede off the record that it has got out of hand.
It is being used in cases where the crime is not serious enough to justify the intrusion.
Infamously, the governor of the Bank of Italy, Antonio Fazio, recently had his telephone tapped.
Latest victim? The scandal that hit Fazio was sparked by a wiretap
He was suspected of interfering inappropriately in a bank takeover deal.
But does that really justify a police officer listening in to all his phone calls, many of which were presumably highly sensitive financially?
Prime Minister Silvio Berlusconi thinks not, and he has introduced a bill proposing that phone-tapping be restricted to terrorism and organised crime.
There appears to be broad agreement that the measure is worthwhile, even from a judiciary that is suspicious of changes in the law by the prime minister, which in the past have often proved helpful to his own legal difficulties.
Also in the bill is a section making the publication of transcripts of telephone intercepts illegal.
That may prove disappointing for the Italian public, who have enjoyed reading the embarrassing titbits that often make it on to the front pages.
Daniel Sandford's film can be seen on Newsnight on Monday 10 October at 2230 BST.