WhoIsCalling.me.uk

Who called from 0300 123 2323

A UK-wide 03 number.

How to block it

Did this number call you? What was it?

No one has reported this number yet. Reports appear here once 3 people have told us about it.

One report per number from each visitor. If you choose again, your new answer replaces the old one. By sending a report you agree to the terms of use. How reports work.

Who lists this number

We only show numbers an organisation publishes on its own website, with a quote from that page and the date we checked it.

NHS Blood and Transplant

This number is listed by NHS Blood and Transplant on its own website as a number it may call you from (Calls to blood, plasma and platelet donors about booking or existing donation appointments).

Source: “We may occasionally try to contact you from 0300 123 23 23.” (opens in a new tab). Checked 14 October 2026.

Every number NHS Blood and Transplant publishes

This could still be a scam call

Criminals can make their number look like a genuine one (this is called spoofing). If someone calls from this number and asks for money, bank details, a code or passwords, hang up. Then call NHS Blood and Transplant back on a number you've found yourself, such as the one on their own website or on a letter or bill from them.

Safe ways to check

What Ofcom’s records say

Number type
UK-wide 03 number
Area or region
UK-wide
Not linked to a place
Cost to call
No more than a landline call
Costs no more than a call to an 01 or 02 number. Usually included in call allowances.
Allocated to
BT
This is the provider Ofcom allocated the number block to. It is not the caller, and the number may have moved network since.
Ofcom status
Allocated
Block 0300 123 xxxx
Allocated on
26 March 2007
Date Ofcom allocated the block

Source: Ofcom numbering data, files published 7 October 2026, checked 13 October 2026

See the 0300 123 xxxx range for the Ofcom facts about the whole block and any numbers in it that organisations or visitors have told us about.

What the provider and number type mean

Numbers starting 03 are UK-wide numbers that are not linked to a place. Organisations use them as a single national contact number. Ofcom reserves 030 numbers for public sector and not-for-profit bodies.

Ofcom allocates phone numbers to communications providers in blocks. The provider shown is the one Ofcom allocated this block to. It is not the person or business that called you, and the number may since have moved to a different network, because people can usually keep their number when they switch provider. Ofcom does not hold information about individual numbers.

Ofcom's rules say calls to 03 numbers must cost no more than calls to 01 and 02 numbers, and must count towards any inclusive minutes you have for calls to 01 and 02 numbers.

Report or block 0300 123 2323

Reporting helps networks and the police find the people behind scam calls. Blocking stops this one number, though scammers often switch numbers.

Report it

Block it

Your mobile network’s own help pages

Landline? See how to block calls on a landline.

Every link above goes to the organisation’s own page and was checked on 13 October 2026. More detail: report and block guide.

Is this your number? You can ask us to clear the visitor reports about it.

Sources and checks

This page relies on:

Checked on 13 October 2026. Read how reports work. How we check our information. Spotted a mistake? Tell us and we will put it right.