The proposals for Everton Football Club's new Kirkby stadium have been attacked by the Commission for Architecture and the Built Environment.
In a report issued in March, but only just made public, CABE raises concerns over the proposed new 55,000-seat stadium and Tesco superstore, saying it would be a 'lost opportunity' and would 'have a detrimental effect on the town and is not of a standard that Kirkby deserves'.
The report also details the disquiet CABE has over the decision to choose Barr Construction to design and build the stadium, despite Everton having also employed KSS Design Group as a 'specialist stadium advisor', and concludes that the plan should be refused planning permission.
It said: 'We are concerned that the stadium design is being delivered by a Design and Build contractor.
'It is our view that Design and Build contracts can produce successful outcomes only when high-quality design is embedded in the process; we do not feel that this has been achieved in this case.'
Broadway Malyan's £400m masterplan also came under fire, with CABE criticising the proposal's lack of flexibility or credibility as the basis for a distinctive new town centre in Kirkby.
The report said: 'While we welcome the development of the proposed uses on this site, we feel that this scheme is, at best, a lost opportunity.'
The controversial plans have already been met with huge opposition in some quarters. Developer St Modwen has lodged an objection to the plans because of concerns over a negative impact on Project Jennifer, in north Liverpool, while planning officials in the Sefton borough have advised that the authority objects to the plans because of their potential to harm nearby towns Bootle and Southport.
A spokesman for Everton FC said: "Very few major projects of this size over the past decade or so have actually been given [CABE's] blessing.
"The CABE report is actually several weeks old now and it's important that people realise it was written and then released before several alterations were made to the "Destination Kirkby" masterplan."