HMRC's official rate of interest remains at 2.5% from 6 April 2017.

Actual and average rates for earlier years:

 

Year 

 Rate

%

 2017/18 onwards 2.50
 2015/16 to 2016/17 3.00
 2014/15  3.25
 2010/11 to 2013/14  4.00
 2009/10  4.75