Tideway issues first blue bond in sterling

London super sewer builder Tideway has claimed a financing first: becoming the first corporate to issue a ‘blue bond’ in sterling.

Blue bonds – a subset of the better-known green bonds (of which Tideway has already issued 18) – are designated to denote specific investor benefits to seas and marine environments. The proceeds from this £250m eight-year blue bond will provide Tideway with additional liquidity for the super sewer system acceptance period, which is due to be complete in 2027.

Tideway CFO Mathew Duncan said: “With the super sewer now protecting the tidal Thames, including therefore the Thames Estuary and the North Sea, it’s wonderful to be able to offer blue bonds in the UK for the very first time. Blue bonds emphasise the importance of the sustainable use and protection of water resources, highlighting the main purpose of the company – cleaning the river.”

Since the tunnel was fully connected in February 2025, there have been zero sewage discharges from the spill points to which it was connected.