The SPD, adopted at a meeting of the London Borough of Lambeth’s cabinet earlier this week, requires the submission of a financial appraisal if the proposed affordable housing provision is below the applicable target level of provision - 50 per cent where public subsidy is available or 40 per cent without public subsidy.
In a statement, Lambeth Labour Party, which runs the council, said that the information will be publicly available and not redacted.
It said that the new rules make clear that the council’s starting position is that "appraisals should be treated transparently and be available for wider scrutiny, helping to end the damaging perception that deals with developers are done behind closed doors and are not transparent, clear or fair".
The SPD states: "Viability appraisals should be submitted without redaction.
"In submitting information, applicants do so in the knowledge that this may be made publicly
available alongside other application documents."
The move follows guidance published by London mayor Sadiq Khan in August which allows developers that, without public subsidy, provide 35 per cent or more affordable housing on schemes in the capital to avoid having a viability appraisal.