Zoopla Property Group (ZPG), which owns Zoopla and PrimeLocation, will pay £160m for the site, and a supplementary performance-based fee of £30m. Zoopla shares leaped by 14 per cent (to £2.10) at the news, but prices remain below flotation rates (of £2.20); when the company debuted last June, its market value neared £1bn.

A spokesperson for ZPG said the company would move to merge the two sites into a single portal, in a “natural step” that would create a unified platform for consumers to locate and manage their new home. ZPG chief executive Alex Chesterman dubbed the deal “transformational”.

Zoopla was founded in 2007, and accrues almost 44m unique visitors per month; uSwitch began life in 2000, and attracts around 50m visitors annually. Last year, it generated a profit of £16m on a revenue of £63m.

In recent months, Zoopla has lost significant market share to competitor OnTheMarket.com, which claims to draw 90 per cent of its agents from Zoopla – and has the backing of many high street estate agents.

Previous institutional backers LDC (the private equity arm of Lloyds Banking Group) and Forward Private Equity will not retain any stake in the business. LDC is the largest beneficiary of the sale, making 2.4 times its original investment of £35-40m in the process; in the past year, LDC has made over £715m from exiting investments.