Peer-to-Peer (P2P) is one of several functions that were amalgamated under the Google Pay name in 2018. It has still been available in the UK market, however, and allows users to send payments to others using a balance stored in a relevant account. Unfortunately, Google has announced that it is suspending this ability in September 2019.
https://www.notebookcheck.net/Google-will-terminate-its-UK-P2P-service-later-in-2019.424785.0.html