A leaked report into defects at the beleaguered Clissold Leisure Centre in Hackney, east London, claims neither Hodder Architects nor engineer Whitbybird were to blame for the basement flooding.
Instead, the top-secret document, drawn up by Arup, points the finger at centre operator Leisure Connections for the problem, which caused the £30 million pool to close in November 2003.
According to the report, errors made 'in plant operation or failure by the operator to monitor conditions in the basement plantroom' were to blame for the flood.
It goes on to say that a coldwater tank overflow was unlikely to have been at fault, because the problem did not arise during a period of heavy rainfall, as claimed by the operator.
However, the report reveals that plastic debris had been found blocking a sump pump.
The report says: 'This evidence reinforces my opinion that the cause of the main flood was the result of operator error.' The revelations will be welcomed by both Hodder and Whitbybird as they head for a mediation with Hackney council at the end of the month.
But a spokeswoman for the council was unwilling to speculate about the impact of the disclosures on the case. She said: 'Hackney council will not comment on this matter due to ongoing legal action.
'The council takes unauthorised disclosure of confidential documents very seriously and the monitoring officer is launching a full investigation into the source of this disclosure.' Should the mediation fail, the dispute would come before the High Court in October.