Rock Feilding-Mellen is the son of the colourful Countess of Wemyss and March. His development vehicle, called Socially Conscious Capital, has applied to East Lothian Council for planning permission in principle to build a mixed-use development at Longniddry.
His mother and step-father, the earl, are also shareholders of Socially Conscious Capital.
It is proposed that the new village expansion will be built around Longniddry Farm, to the south of the existing village, on land owned by the Wemyss and March Estate.
There has been a substantial local campaign against the plans, which have been in development for several years.
Mr Feilding-Mellen said: "In addition to the much-needed new housing, we wanted to make sure that there will also be tangible benefits for the existing residents of Longniddry, such as employment opportunities and community facilities, and that these are fully integrated with the existing village.
“With its close proximity to the railway station, this makes our development one of the most sustainable in East Lothian, and was one of the key reasons the site has been included in the council’s draft proposed local development plan.
“We have undertaken extensive community consultation on our proposals and would like to thank those who submitted their views, which we have done our best to try and incorporate into the final proposals.”