"The estimated cost of the project has escalated, from £1.7bn in 2004 (including Stratford to East Ham part and sewage treatment civil engineering construction movements (STW) costs) to £2.2bn in 2007 (also including Lee Tunnel and STW costs) to £3.6bn now for the shorter Thames Tunnel as far as Abbey Mills, plus some £1bn for the Lee Tunnel and upgrade of works at Beckton. The total costs of all the Tideway schemes have therefore increased from £1.7bn six years ago to £4.6bn today (all costs at relevant year prices). There is no guarantee that the current estimate will not be subject to further escalation."