JUSTIN BIEBER WHOLE LOTTA ROSES ... Sofia Back in the Game

Everything's coming up roses for Justin Bieber in London, and he shared the love with a group of adoring Beliebers ... and possibly his old gf.

Justin's "Purpose Tour" hit London town Saturday night, but before heading to the after-party at Tape nightclub, he took time to hand out red and pink roses to the screaming fans waiting outside.

We're told he dropped about 100 pounds with a street vendor for the flowers -- but even more interesting is the fact Sofia Richie was also at the club.

They didn't go in together and she walked out solo. Unclear if the bachelor Biebs saved a rose for Sofia. But yes ... we're saying there's a chance.