The property investment company has sold 35/50 Rathbone Place to Rathbone Place Jersey Limited, an entity owned by WestInvest Gesellschaft Investmentfonds mbH and Deka Immobilien Investment GmbH.

The mixed-use development is currently under construction with phased practical completion expected from late March 2017 and contains office space pre-let to Facebook on a 15-year lease.

The estate also contains 142 private residential units of which 139 have already been exchanged for sale.

Great Portland Estates revealed that the sale reflected a net initial yield to the buyer of 4.25% and is expected to crystallise a whole-life capital return of around £110m, which is proposed to be returned to shareholders by way of a special dividend.

“Rathbone Square is our largest ever development scheme and this sale continues our successful strategy of recycling capital out of assets where we have created significant value,” said Toby Courtauld, chief executive of GPE.

“Having purchased the site in late 2011, obtained an attractive planning permission and commenced construction in early 2014, we pre-sold the vast majority of the residential units in summer 2014 and secured one of the largest ever lettings in the West End a year later.”

GPE was advised on the sale by CBRE, GM Real Estate, Nabarro, BofA Merrill Lynch, JP Morgan Cazenove and Lazard.