The source If anyone is interested to read more:
http://www.cnbc.com/2017/06/26/barclays-bitcoin-regulators-fca.html
I sadly don't believe that the banking system will ever adopt bitcoin, If they start doing so, It would be for a particular reason they hide (most likely to eventually control bitcoin). The maximum that could happen right now is making bitcoin legal in some countries.
I think the bitcoin implementation can cut the costs to the banks. So they might embrace it.