Britain’s biggest online property portal, Rightmove, is so overwhelmingly dominant in its own market that its CEO Johan Svanstrom publicly refers to his company as “unassailable” and “a fortress”. Yet Australian suitor REA is hoping a £6.1 billion ($11.9 billion) bid could yet be enough to give Rupert and Lachlan Murdoch the keys to the castle.

REA, which is 61 per cent owned by Murdochs’ News Corp, on Monday hastily launched a third informal cash-and-scrip offer for Rightmove. If this can break down the initially trenchant resistance of Rightmove’s board and some of its investors, REA will get its hands on a cash cow whose revenue model is impervious to the £8.7 trillion British housing market’s ups and downs.