Market value of government bonds in the United Kingdom 2000-2021

The source added the following definitions "Conventional gilts: Conventional gilts are the simplest form of government bond and constitute around 75% of the gilt portfolio. A conventional gilt is a liability of the Government which guarantees to pay the holder of the gilt a fixed cash payment (coupon) every six months until the maturity date, at which point the holder receives the final coupon payment and the return of the principal. The prices of conventional gilts are quoted in terms of £100 nominal. However, they can be traded in units as small as a penny."

"Index-linked gilts: Index-linked gilts (IGs) form around 25% of the gilt portfolio. The UK was one of the earliest developed economies to issue index-linked bonds for institutional investors, with the first issue being in 1981. As with conventional gilts the coupon on an index-linked gilt reflects borrowing rates available at the time of first issue. However, as index-linked coupons reflect the real borrowing rate for the Government rather than the nominal borrowing rate there is a much smaller variation in real yields over time."