The National Laboratories of many European countries provide time information in a standardised format, an ITU-R Recommendation (ITU-R TF583.4). Information is provided over a dial-up modem, with one 78-char segment every second. A description of the time code is available at https://www.ptb.de/cms/en/ptb/fachabteilungen/abt4/fb-44/ag-442/dissemination-of-legal-time/dissemination-of-time-via-the-public-telephone-network/the-european-telephone-time-code.html
The following countries have traditionally provided this service: Austria, Belgium, Germany, Italy, The Netherlands, Poland, Portugal, Romania, Spain, Sweden, Switzerland, Turkey and United Kingdom.
Note that the service is usually available from outside the country as well, as long as you are willing to make a long-distance phone call.
Some examples are:
In Germany, Physikalisch-Technische Bundesanstalt (PTB)'s timecode service. Phone number: +49 5 31 51 20 38.
For more detail, see https://www.ptb.de/cms/index.php?id=1786&L=1
In the UK, National Physical Laboratory (NPL)'s Telephone Time Service. Phone number: 020 8943 6333
In Italy, L’Istituto Nazionale di Ricerca Metrologica (INRIM)'s CTD service. Phone numbers: 011 39 19 263 and 011 39 19 264
For more detail, see https://www.inrim.it/res/tf/ctd_i.shtml
In Sweden, SP Swedish National Testing and Research Institute’s timecode service. Phone number: +46 33 415783.
For more detail, see https://www.sp.se/en/index/services/time_sync/modem_time/Sidor/default.aspx