According to a Royal Borough of Windsor and Maidenhead planning report, applicant Windsor Racecourse Co Ltd had sought full planning permission for the hotel on a 1.19-hectare site to the north of the A308, within the the Royal Windsor Racecourse.
The report said that the proposed development "is defined as inappropriate by green belt policy and guidance and is harmful by virtue of its inappropriateness, the loss of openness and the intensification of built development in this predominantly countryside location".
However, planners concluded that the applicant had successfully argued that very circumstances existed to justify the development within the green belt.
The report said that the case was "largely based on the public benefits of providing a hotel in Windsor to meet the need for tourist accommodation and the need identified for conferencing facilities" and this was supported by the council’s emerging local plan.
The report also said that the hotel would allow "further diversification" for the racecourse and that "clear that benefits would also accrue in giving opportunity for a greater appreciation of the river Thames setting, enhancements to ecology and knowledge of the archaeology of the area".
"Taken together it is considered that these factors amount to very special circumstances and can be afforded significant weight in the planning balance", the report said.
The application was approved at a meeting of the council’s planning committee last week.