The developer made a record pre-tax profit of £68.9m for the six months to September 30 compared to £5.2m last time as the London property revival started to spread to the rest of the country.

Chief executive Michael Slade said: “We have had an outstanding first half of the year and we look forward to announcing further improvements in our full year results to 31 March 2014.

“We are long both in central London offices and in high yielding secondary regional assets, the former to provide capital growth and the other to generate income and cash flow.

“This has been our aim and strategy for the last three years and I firmly believe we are reaping the rewards as London continues to grow and investors move up the risk curve and into the regions.”

The main driver of profits have been Helical Bar’s Brickfields White City job where land was sold on after planing permission was granted and 200 Aldersgate Street in the City of London which was refurbished before selling.

The firm said: “The first half of the financial year has been dominated by the culmination and outstanding success of the projects at White City, London W12 and 200 Aldersgate, London EC1, both of which exemplify the ‘Helical model’ of applying limited equity to create substantial performance.

“These projects have resulted in a net cash receipt by the Group of £65m, an extraordinary return on a £1.5m total investment.”

Helical Bar’s largest current development is Mitre Square in the City of London where demolition is complete and construction will start on a new £250m office block “once a financial partner has been signed up.”