Brexit risks are not priced in by bond markets and Britain's exit from the European Union could turn more bitter than expected, the deputy director of the National Treasury Management Agency warned today. 

"To me (Brexit) is an area that isn't priced into markets and it can't be because no one knows what it looks like, even a hard Brexit,"  Anthony Linehan said.

He made his comments at a conference in London today. 

"The one thing that worries me is, it's like a divorce, a hard Brexit could turn very bitter and nasty and the reality of it could be very difficult for financial markets," the NTMA's deputy director said. 

Britain is one of Ireland's biggest trading partners, and the Northern Ireland border is a key issue in Brexit talks.  

Mr Linehan said that changes at the European Central Bank and European Commission constitute political risks, alongside Brexit, which he sees as more of a concern than financial risks. 

He added that the change of ECB chief will not herald a significant shift in policy stance. 

Mario Draghi's term as ECB president expires at the end of October.