The telephone has been a lifesaver from the outset. For the first time people at risk in homes or offices were able to call for help without having to run out to the street.
Before too long, special networks and services were put in place to ensure that emergency calls could always get through.
The 999 service - a dedicated memorable number for summoning the police, fire or ambulance - dates from 1937.
In 1935, five women were killed by a fire in London's West End. A neighbour complained that she called the operator on 0 to summon help - but that the fire brigade arrived before the exchange answered her call. The 999 service was then set up to ensure that all emergency calls had priority treatment.
The code was chosen for several reasons. Having decided on a 'three digits the same' code (necessary for the London network), some combinations were immediately ruled out. '111' would have been the quickest code to dial, but numbers beginning 1 were not then used. '222' was already in use (it was the digit equivalent of the ABBey exchange) and 0 was already the code for the operator.
Most of the other digits could have been used but the final choice came out of a need to ensure that emergency calls could be made from kiosks and other public telephones, without needing to insert any coins. This was already the case for non-urgent calls to the operator - a special dial allowed free dialling of the digit 0 - and it was a relatively simple task to extend the facility to the digit 9 too.
Many of the stories featured on the BBC TV series '999' provide graphic examples of the life saving powers of the mobile phone.
Take Kevin Burgess, for instance. While hunting with a shotgun in a dense forest near Dundee Scotland, Kevin fell into a ditch, causing his shotgun to go off and hit him in the leg. Lying at the bottom of the ditch, he called the emergency services on his mobile phone and was put through to ambulance controller Steve Robertson.
Steve immediately realised that the wound was deep and that Kevin would bleed to death before the ambulance could reach him. Steve talked to Kevin over the mobile and helped him put a tourniquet in place to stem the flow of blood. Steve then kept Kevin talking and conscious until the paramedics reached him.
Without his mobile phone, Kevin would certainly have died.
The arrival of the telegraph and telephone meant that people could get in touch quickly, which was especially useful if you needed help in a hurry.
The emergency services soon warmed to this idea and started to put telegraph alarm points - and later special telephone boxes on the streets in urban centres, which gave both policemen and the general public a hotline to the police station.
The PA1 was the standard police telephone pillar used in the 1930s, which was later replaced by the PA3.
The pillar telephones fulfilled a need and people used them to ask for directions or seek advice, particularly in central London, as well as for emergencies. In the end, policemen were stationed beside the pillar in Piccadilly Circus to deal with the public directly. This was perhaps the most well known of all PA3s and is now officially preserved as a 'listed building'. However, today all is not as it seems. The original pillar 'disappeared' and the unit there now is a recycled spare.
One vital benefit of the telegraph was the speed, with which it could summon the emergency services.
This Gamewell fire alarm system allowed the public to call the fire brigade immediately, using senders located around the area covered. Manchester had a particularly extensive public system, and similar installations were installed in large private houses, royal palaces and business premises.
All someone needed to do was break the glass and pull the lever. The sender then transmitted a telegraph message to a central station, identifying the location and raising the alarm.
A printer connected to the central control equipment provided a permanent time-stamped record of the incident.
This film informed the public about the correct procedure for calling the emergency services.
Emergency calls receive priority attention and are switched through to the appropriate emergency service.
For security and to discourage hoaxers, callers are always asked for their location and telephone number..
Play the video to learn more. A new window will open.Marjorie Chapman, was born in 1920 in Willesden Green, north London to a normal working class family. Neither she, her family or friends had a telephone and she didn't actually use one until she joined the GPO as a telephonist in 1935, when she was 15 years old.
Long since retired, she talks about the essential service provided by the Piper emergency line and how it helped her after she had suffered a nasty fall.
Play the audio clip and view the transcript to learn more. A new window will open.Mrs Barbara Flux, born in 1924, grew up in Weymouth the daughter of hoteliers, which she subsequently became herself. Her family had a phone from an early age to enable people to book rooms at the hotel, although confirmation was always followed up with a deposit in writing.
Retired from the business today, she talks about how the phone has become an even more essential communication tool since then, and in particular her reliance on the Piper emergency line to provide essential ease-of-mind during old age.
Play the audio clip and view the transcript to learn more. A new window will open.