source "$( dirname "${BASH_SOURCE[0]}" )"/complete.bash

PS1="\[\033[01;34m\]\$(basename '$VIRTUAL_ENV')\[\e[0m\]$PS1"

source "$( dirname "${BASH_SOURCE[0]}" )"/complete.bash

[[ -z "${VIRTUAL_ENV}" ]] || PS1="\[\033[01;34m\]\$(basename '$VIRTUAL_ENV')\[\e[0m\] $PS1"

Put a space after VIRTUAL_ENV basename
Put a space after VIRTUAL_ENV basename 

Before:
VEhost ~ $

After:
VE host ~ $