If you are looking for assistance with a UK visa application you can call the UK Visa and Citizenship Application Services team on +44 (0) 300 7906 268. This number is an English language service and can be used for visa support for applicants outside the United Kingdom. For example if you are in Tehran you can phone this number if you are having difficulties with or need advice about the process of applying for a visa for the UK.
The UK Visa application helpline +44 (0) 300 7906 268 will connect you to UKVI in Birmingham.