No, calling London phone numbers starting with 020 area codes is not free of charge on Vodafone tariffs.
020 telephone numbers are registered to personal and business addresses within the UK capital city of London, therefore they are one of the most widely-used set of numbers in the country. Unlike calls to freephone helplines you cannot phone 020 numbers for free on Vodafone tariffs, under normal circumstances you will have to pay a per-minute charge as well as a connection fee which depends on either your pay as you go deal or monthly contract rate.
How to avoid charges when phoning an 020 number
You can avoid paying any call charges when phoning an 020 number from a Vodafone device if you get inclusive minutes to use on your monthly allocation or pay as you go bundle. This is because Ofcom rules stipulate that these minutes can be used to call all local 01 and 02 phone numbers for free, as well as national helplines beginning with the non-geographic 03 code.