In reply to a post by Philce:

Im sure I read something about the technicalities of the merger of the 2 networks and in-call roaming between Orange and T-Mobile some time ago. Something about the technical achievement of getting the different radio kit to talk to each other (Ericsson and Nokia I think it was?).

Yes I think this was incredibly clever and made the 2G network seem less. Then there was the court case from Arqiva against EE which stopped the 3G integration, and once that was resolved (EE won) the 4G decision from Ofcom had occurred, so EE was permitted to roll out 4G on the existing 1800mhz - so the rebranding started fast.

I don't think they just left 1 network working and ripped out the other.

Except in Northern Ireland, correct.

My phone regularly changed between "Orange" "T-Mobile" and "Orange T-Mobile" on the display before I got upgraded to a EE sim. (that was with a Orange and T-Mobile SIM in different phones).

Likewise.

Will be interesting to see what happens if the 3/O2 merger is allowed because I use O2 in a company supplied phone and the coverage is diabolical out of town. 3G is almost non existent. Vodafone is worse, and as others have said they will have to lots of upgrading to keep up.

Where vodafone have rolled out 4G it is a dramatic improvement, my work is with vodafone and it was awful only 18 months ago, and now its amazingly better (3G and 4G).

O2 and three is one to watch, I think it won't be allowed to be honest.

Lots of EE sites are 2G and 4G only.

VOLTE should being rolled out soon I imagine... In London - in many areas, if you start a call on WiFi calling and then leave your home, your call already falls back onto 4G and works just fine over LTE (assuming you have 4G set to both Voice and Data).

A standard call made still goes back to 3G though. Outside of London this same behaviour I did not observe.

In reply to a post by ukhardy07:

Lots of EE sites are 2G and 4G only.

VOLTE should being rolled out soon I imagine... In London - in many areas, if you start a call on WiFi calling and then leave your home, your call already falls back onto 4G and works just fine over LTE (assuming you have 4G set to both Voice and Data).

A standard call made still goes back to 3G though. Outside of London this same behaviour I did not observe.

That is interesting, and could be just your account. I've seen posts elsewhere that said that VoLTE is only actually active currently in parts of Hatfield and Bristol (obviously where there are EE offices!) on the 1800 freq (and maybe 2600).

The big change will be VoLTE on 800mhz; when that launches the amount of fallback to 3G should reduce.