LONDON (BLOOMBERG) - London's stock of completed but unsold homes has surged by almost half this year as Brexit uncertainty and affordability issues dog the housing market.

The number in the capital jumped to 2,374 units as of Sept 30, the most on record and up from 1,595 at the end of 2017, according to data compiled by Molior London. The borough with the biggest stockpile is Wandsworth, an area that borders the River Thames, followed by Croydon, an outer borough in the south of the city.

"Some of this excess has built up because it's the wrong product at the wrong pricing for what people want to, and can afford to buy," said Tim Craine, founder of the property research firm. "For the rest, it's a case of bad timing due to the lull in the market that's come about due to Brexit."

Sales for properties in London and its commuter belt in southern England are drying up as high prices, uncertainty over the economy and tax rises make buyers cautious or unable to get on the property ladder. It now takes the average Londoner 14.5 times their annual salary to purchase a home, the highest multiple ever, according to Hometrack.