A row has broken out over claims Barnet Council could have lost out on millions of pounds in developer payments for affordable homes.

Labour leader Barry Rawlings claimed the council could have missed out on the cash because of a failure to publish financial viability assessments (FVAs) – used to work out how much affordable housing developments can support – when planning applications were submitted.

But members of the Conservative group strongly denied that the council had lost out on any money, with one Tory councillor branding the suggestions a “fantasy”.

Developers unable to meet a 35% affordable housing target are required to submit FVAs with planning applications to show how much affordable housing can be provided. If none can be built on site, developers can make payments to support provision on other schemes.

In September, Cllr Rawlings submitted a member’s item calling for an investigation into how much money in affordable housing commuted payments may have been lost to the council from all planning applications. It came after the council initially accepted a developer’s proposal that only £900,000 was due for a scheme in West Heath Road, Hampstead, but later upped the payment to £6million following an independent report into the FVA.

The council’s policy and resources committee received a report on Wednesday detailing the findings of a review of 46 planning applications, which was carried out following Cllr Rawlings’ request. It revealed that more than a third of the schemes provided affordable housing on site. The council secured £8.2million from the remaining applications because the FVAs concluded the proposals could not support on-site affordable homes.

But Cllr Rawlings branded the report “inadequate” and said it had “nothing to do” with his member’s item. He said that at the end of 2021 there was “great difficulty” finding FVAs published by the council, despite government guidance coming out in 2018 stating that they should be published.

The Labour leader said FVAs should form part of proper decision-making by planning committees, and pointed out that a recent decision was challenged in court because the FVA had not been published.

Cllr Rawlings said the Labour group had found ten unpublished FVAs that could have been open to legal challenge and expected to find more. He said: “What we have not got [in the report] is, what is the potential loss in commuted sums over the last three years? We know it runs into millions and we will never get that money back, and it means the residents of Barnet have been short-changed.”

Council leader Dan Thomas claimed the report was in line with the remit of Cllr Rawlings’ member’s item and said the Labour leader had “no proof” that millions were lost.

Conservative committee member Peter Zinkin said new proposals had come forward for a care home at the West Heath Road site, meaning the council did not get any money from the proposed housing scheme. He said: “The idea that, from this fantasy that you have created, the council has lost millions of pounds, is just not correct.”

Cllr Zinkin said the council had accepted there was a “degree of inconsistency” in the way planning officers were treating the publication of FVAs but this had now been corrected. He added that the council would go back and deal with the ones that had not been published to demonstrate there had been “absolutely no loss of value”.

Labour’s Cllr Alison Moore said the fundamental issue was that the failure to publish some FVAs meant councillors had been denied the opportunity to “exert due scrutiny” when taking planning decisions, and that raised questions about whether the council was being “assertive enough about chasing affordable housing in those big planning applications”.

Cllr Thomas said unpublished FVAs would be published “as soon as possible”. He added: “[There is] nothing to hide with those reports. I regret that they were not published at the time. I think had they been, they would have shown exactly that there has been no loss to the council.”

Following the debate, Conservative committee members voted for the report that was produced in response to Cllr Rawlings’ request. Labour members and Liberal Democrat Gabriel Rozenberg voted against.