'Super Voice' 4G service from Three offers better signal

Three is making use of a lower frequency 4G spectrum that can travel more widely

Mobile phone provider Three has launched a UK service it says will improve reception inside buildings and in rural black spots.

Its 4G Super Voice enables customers to make calls and send texts using a lower frequency spectrum.

Other networks are looking into introducing the technology, known as Voice Over Long-Term Evolution (VoLTE).

It currently works on only the Samsung Galaxy S5, but recent iPhone handsets will be added in the coming months.

It is being rolled out in:

• London

• Edinburgh

• Exeter

• Birmingham

• Cardiff

• Manchester

• Liverpool

• Bristol

Three said up to 5.5 million customers would have access to the service by 2017.

Chief technology officer Bryn Jones said: "By the end of the year, one million of our customers will have access to better indoor coverage and be able to use their phones in more places than ever before."