Thousands of furious mobile phone customers have been left unable to make or receive calls after the Three network went down for an entire day.

Some users said they were still experiencing problems this evening after a major outage took out "voice services" on the mobilenetwork operator, which currently has 10.5 million active customers in the UK. Three - which recently announced a £16.5 billion merger with rival Vodafone - said it is "continuing to investigate" the problems and was "so sorry" to customers who have been affected. While the network says that data services are unaffected, some have said they are also unable to connect to 4G and 5G. Here's everything we know about the Three network outage:

READ MORE: Three down LIVE: Network outage sees users unable to call or send texts

The outage affecting the Three network started at around 7.45am this morning, according to Downdetector.

It's left many customers unable to receive or make phonecalls - with some taking to social media to complain that they had missed important calls from work, family members or their doctor as a result.

Three have been providing updates on their X (formerly Twitter) page throughout the day, and said in its first response at 9.36am: "We're aware of an issue affecting voice services and are working hard to fix it."

According to Three, while many customers have been unable to make calls during today's outage, data services such as 4G and 5G should be working as normal.

But some users have got in touch with the Mirror to say that they have also experienced problems with their data connection, in addition to the issues with telephone and SMS services.

iD Mobile, which also uses the Three network, has also confirmed issues with calls, text message's and the Live Chat function this evening.

Customers on Smarty mobile, which is owned by Three, are also reporting issues.

After approval from Competition and Markets Authority (CMA) earlier this year, Three UK recently merged with Vodafone in a bid to create a "new force in UK mobile."

However, Three customers can't use Vodafone's network just yet.

In the FAQs section of its website, Vodafone says that "from mid-June" Three UK customers would receive a 20% boost in 4G data speeds, and that "within a few months" Vodafone and Three customers would be able to "automatically use each other's networks".

It means that today's outage has likely come too early for Three customers to benefit from the merger.

Though reports of the outage dipped on tracking services such as Downdetector later in the day, some customers say they are still experiencing problems.

In an update this evening, the mobile network said: "We’re continuing to investigate an issue affecting voice services on our network. Data services remain unaffected, so customers can make calls using third-party messaging apps. A small number of text messages are also impacted.

"We understand how frustrating this is and are so sorry if you've been impacted."