An investment bank says the price of new-build upmarket London flats could fall by as much as 20% this year.

The warning is from Morgan Stanley and comes in the context of supply of expensive new developments in areas such as Canary Wharf and Battersea.

The bank said that it was “assuming a 10-20% fall in new-build high-end residential pricing in 2016” as it lowered its rating on Capital & Counties, the firm regenerating the 77-acre site at Earls Court.

Trevor Abrahmsohn, head of agent Glentree International, told the London Standard: “Asian buyers — from Malaysia, Singapore, Hong Kong and China — are walking away from their commitments to buy properties in, for instance, east London and Nine Elms.”

“They would rather lose 10% than complete the purchase and lose a lot more, even before the developments are complete.

“The changes to buy-to-let tax is the straw that broke the camel’s back.”