By Sarah Toyne
BBC News Online consumer affairs reporter
The Number's twins: A new take on directory enquiries
The plug is finally pulled on the UK's single directory enquiries service on Sunday after 46 years, but navigating through the array of new services can be baffling.
The move to open up both international and national directory enquiries to competition is one of the last pieces in the jigsaw of telecoms deregulation. The business was worth £300m to BT last year.
The easy-to-remember 192 and 153 will be replaced with a series of six-digit numbers, prefixed with 118.
But with 20 services to choose from, getting the right price and the best service for your needs can be confusing, and that's without remembering which 118 number to call.
Use the box on the top right-hand side of the page to tell us your "118" experiences.
The big switch
So, what do they cost - and how do I get the best service for me?
The charging structure varies widely between providers, and also depends on the line you are calling from.
There may be a fixed charge for calls, or a charge per minute while the call is connected, or both.
Other services also levy an initial connection charge when you call up the operator, in addition to the per minute charge you pay while on the phone.
As with other types of phone calls, where you are dialling from - whether it is a BT line, a cable company or a mobile phone - will also affect the call charge.
Some companies offer unlimited searches, while some will restrict your choices to one per call.
Consumers using BT lines can find out the costs of calls to the new international and national services from a special website, called Newdirectoryenquiries.com, which has been created by the industry.
Finding out the cost of calls from mobiles and cable companies is more difficult, but there are links to some of the relevant pages of the company's websites on the Oftel website.
BT's existing 192 service charges 40p for searching for up to two numbers.
Some of the new services will be considerably cheaper.
Directory Enquiries UK, is a British company with a South Africa based call centre that is used to handling emergency service calls.
Think before you dial
While your call will be answered thousands of miles away, the site offers the cheapest calls to national directory enquiries, relative to those providers listed on Newdirectoryenquiries.com.
Calls are charged at a flat rate of 19p a minute and the service offers unlimited searches.
Isabel Magan, director and co-founder of the service, says the company won't be forced to push up prices dramatically when the market settles down.
"We are not loss leading. We are still making a margin at 19p," she says.
"We don't have to hike it up to recover costs."
Points to watch
Not all the directory enquiries services are the same, and while some may appear expensive, when it comes to the world of 118, not all is what it seems.
For example, dialling The Number's 118118 national service might be quite expensive, but it also offers a few extras, such as cinema listings and hotel bookings.
And, if the operator puts you through to the number you have requested, you will be charged a relatively low rate of 9p a minute for the duration of your new call.
Yellow Pages, in contrast, offers a medium-range price of 40p a minute for an enquiry and unlimited searches (and additional business information like opening hours), but if you ask the operator to put you through to your requested number, you will continue to be charged at 40p a minute for the duration of the new call.
The 118888 service is one of the cheaper services around, and it has a few added extras such as SMS text delivery and business classifieds.
But again, if you ask the operator to put you through to the number you have requested, you will continue to pay 118888's charge of 20p a minute throughout the duration of your new call.
Orange and BT also charge high fees after putting you through to your requested numbers - at 30p a minute.
Most consumers would do better to end the call with the service's operator and then re-dial the number they have requested.
If it is conscience and not price that is your biggest priority, you can even support charities through 118.
Share UK will donate 5p of each call to the British Red Cross and Barnados.
Reassuringly, BT says it will continue to operate its free 195 directory enquiries service for blind and partially sighted people.
People who wish to use the service have to register with BT and are then given a PIN code.
If you still find the whole system baffling, or simply cannot remember your 118 from your 118, you can still call the old 192 and 153 numbers right up until 20 June 2004.
Your call will be greeted with an automated message offering a freephone number, which once dialled will take out the hassle of selecting a service, as it will randomly choose one for you - and tell you what it will cost.
On past experience of deregulation in other countries, what service actually lasts the course will depend on inevitable corporate natural selection.
But while only 20 services are thought to be active at the moment, Oftel has already allocated numbers to a further 60 companies.
Can it become more confusing?