What does it mean when the ATC says "(Airline Name) XXXX with Victor", or Hotel, or Juliet?
When you first make contact with your destination airports ATC you will have listened to the ATIS (weather etc) as this changes periodically it is given a letter which runs A-Z then starts again. Therefore the call to ATC is "Gatwick approach, Speedbird 232 descending fl70, heading 230, 737 with VICTOR" ATC then knows if you have the latest information correct QNH etc. If you don't they will advise. It is also common practice in the UK if cleared to an altitude you read the published QNH.
A similar situation is when calling for push and start. "XXX tower Kestral 823, stand 23B, information Bravo, QNH 1013 request push and start".