South Oxfordshire District Council refused the outline application, which included 40 per cent affordable housing, in September last year.
The proposal would have seen the homes built on agricultural land to the immediate north of Reading suburb Emmer Green.
Last week, inspector Nick Palmer dismissed Gladman's appeal against the refusal, saying that it would conflict with existing and emerging local planning policy and would cause harm to the neighbouring Chilterns Area of Outstanding Natural Beauty.
In his decision letter, Palmer said the development was not consistent with the strategy of the council's 2012 core strategy which states that major new development will be focused on Didcot and other development focused on towns and villages.
There was also no support for the proposals from the emerging South Oxfordshire Local Plan, published in 2017, the inspector concluded.
Palmer also considered the Oxfordshire Housing and Growth Deal (OHGD), which was agreed by central government after the planning inquiry closed.
He said: "Although the proposal would boost the housing supply and in this respect would accord with the overall objective of growth in Oxfordshire it is not supported by the OHGD…"
The inspector said that the development would create jobs through construction and expenditure of new residents.
However, he said the proposal would "unacceptably harm the character and appearance of the area" and "result in the loss of over 13 hectares of best and most versatile agricultural land".
The inspector concluded: "The substantial weights that I give to the harms would significantly and demonstrably outweigh the very significant, limited to moderate and limited weights that I have given to the benefits of the proposal."