In accounts for the year to the end of March, the company, whose central London estate spans 92-acres, also revealed a 9.1% increase in rental income as the strength of the West End office and retail markets outweighed a slowing residential market.

The heirs to the property fortune, which is one of the largest remaining aristocratic London estates, shared dividends of £17.8m during the year.

Toby Shannon, Howard de Walden Estate’s chief executive, said “The main focus of our business is on increasing rental income and profitability over the long term.

“In that context, we are pleased to report growth of 9.1% in our rental income during the year, leading to a 12.8% increase in revenue profits before tax. More importantly, over the four years from 2011 to 2015, rental income and revenue profits have risen by 34% and 38% respectively.”

During the year, the company completed its third private placement, raising an additional £100m at an average all-in rate of 3.63% over 10 to 20 years. Its net debt increased from £287m to £310m, implying a gearing level of 9.3%.

Howard de Walden Estate’s has an capital investment programme to spend more than £200m over five years, providing over 200,000 sq ft of office, residential, medical, retail and restaurant space.