The property had effectively been converted into nine bed-sits with lockable doors on every bedroom and key meters for the gas and electricity supply.
A planning application was submitted in June 2004 to install new dormer windows and convert the loft of the five bedroom, two bathroom family house to create two extra bedrooms at the residence in Beresford Road, N8.
Alert neighbours however reported to local councillors that extensive works were being carried out to other parts of the property.
Houses in the area are subject to special planning controls prohibiting conversion into bedsits due to parking pressure and problems providing off-street parking.
Enforcement officers inspected the site in February and discovered rooms had been reduced in size, six new showers and toilets had been installed, and the large family living and dining rooms had been reduced to make way for toilets and showers.
Further investigations also revealed the house was owned by Limestone Properties Limited, a property investment and management company of which Mr Boukourakis was sole director and shareholder.
Mr Boukourakis and Limestone Properties Limited denied the allegations at the hearing at the high court on 15 April but gave an undertaking they would not let the house, market or sell it for use as a house in multiple occupation without planning permission.
They were ordered to pay£2,500.00 towards the council's legal costs and could be held in contempt of court and liable to a fine or imprisonment if found in breach.
Robin Payne, assistant director, enforcement, said: 'We do not have to wait until a breach of planning permission has occurred before taking the necessary action. If there is evidence of an intended breach we will act expediently as this case clearly demonstrates. It is essential for homeowners and landlords to seek proper planning permission in order to avoid costs of conversion, loss of rent, and devaluation in the potential value of the house.'