Oxford's area code is 01865 and does not contain '44'.
However, written in full international format, you would include the UK's country code of 44.
For example: 01865 234567 would be written as +44 1865 234567 to show overseas callers the numbers they need to dial.
The telephone area code for Oxford is 01865, or +44 1865 in international format. A number beginning with 01865 77 is most likely a BT landline in Cowley; however, with number portability, any 01865 number could be located anywhere in the Oxford 01865 area, served by any local carrier.
Country code +44 is the UK, and +44 7926 is a mobile code, along with the rest of +44 74 through +44 79.
Country code +44 is the United Kingdom. Area code +44 1303 (or 01303 in UK domestic format) is Folkestone.
The country code and area code of Aberdeen, United Kingdom is 44, (0)1224.
The country code and area code of Coventry, United Kingdom is 44, (0)24.
Country code +44 is the United Kingdom.
The country code and area code of Leeds, United Kingdom is 44, (0)113.
Until the early 1990's, area code +44 21 (or 021 within the UK) was Birmingham, which is now area code +44 121 (or 0121 within the UK). There has never been an area code +44 217 (or 0217) in the UK.
The country code and area code of Bracknell, United Kingdom is 44, (0)1344.
The country code and area code of Cambridge, United Kingdom is 44, (0)1223.
The country code and area code of Birmingham, United Kingdom is 44, (0)121.
The country code and area code of Northwich, United Kingdom is 44, (0)1606.