FoE examined NRA data on the compliance of sewage works with their consents over a 12-month period in 1992/3. The group found that 210 failed their consents (see table ).
The Water Services Association responded to FoE's survey by saying that the 210 works represent only 6% of monitored works. The 1992/3 figures represent "a very real improvement" over performance prior to privatisation in 1988, it maintains, when 17% of monitored works failed to comply.
Another point raised by FoE is that the number of prosecutions for sewage pollution brought by the NRA has declined since 1990, even though the number of sewage-related pollution incidents reported to the authority has increased. Comparison of the figures with the NRA's own data on prosecutions (see pp 44-45 ) suggests that some NRA regions have been keener than others in bringing water companies to court. South West Water has the worst compliance record - but has notched up relatively few prosecutions. Despite 77 failures in 1992/3, it was prosecuted only once during 1993.
FoE's data show that Northumbrian Water is well ahead of the pack, with 100% compliance during 1992/3 and a declining trend in prosecutions. Although the company was prosecuted nine times between 1989 and 1992, it was not prosecuted at all during 1993.
The collation of Scottish compliance data is complex due to the varied practices adopted by the seven RPBs, despite guidance from the Scottish Office on the format of annual reports. Although headings and performance indicators have been standardised in recent years, differences between RPBs remain in the classification of discharges, the treatment of discharges with marginal compliance, and the treatment of small discharges which are subject only to visual inspection.
Three years ago, the Scottish Office specified performance indicators covering all the RPBs' functions. But this has not provided a strictly comparable assessment of compliance, dealing only with larger discharges registered in Scottish Office archives.
The Scottish compliance data are not directly comparable with those in England and Wales for another reason. Sewage works consents in England and Wales were relaxed twice during the 1980s to protect operators from prosecution. There was no systematic relaxation of consents north of the border because the different legal system made private prosecutions impossible and relaxations were not needed. The effect has been to retain tighter standards for sewage treatment than England and Wales, although compliance is poorer.