What is accrued interest?
If an investor buys a bond on its first day of issue, or just after the last coupon payment, the price seen on the screen will be the full price. However, when buying a bond part way through its coupon period (for instance 6 months after the last coupon payment for an annual bond), there will be an adjustment for the income that has "accrued" to the bond. This is standard practice in the bond market and strikes a fair balance between buyers and sellers, as well as neatly differentiating between cash flows from income and those from capital gains.
With the majority of non-Gilt bonds, the basis of this accrued interest is calculated on a "30/360" basis. This assumes that each month has 30 days, and each year has 360 days.