The Financial Times today said a vote for Britain to quit the EU in next week's referendum "would seriously damage the UK economy", as it officially endorsed remaining.
With a week to go until a knife-edge vote on Britain's European Union future, the FT as expected came out in support of continued EU membership.
While criticising the "Remain" campaign for its "scaremongering" regarding potential financial consequences of a Brexit, it argued that the "economic costs of withdrawal are substantial".
"A vote to withdraw would be irrevocable, a grievous blow to the post-1945 liberal world order," it said.
The Financial Times, a global business daily, has an estimated 449,000 readers in Britain, according to the latest data from the National Readership Survey.
The Sun, which declared its support for Brexit on Tuesday, has around 4.5 million readers.
The tabloid said it wanted Britons to "reassert our sovereignty" against a "relentlessly expanding German-dominated federal state".
Most other national papers have not yet declared their support, although many are eurosceptic.
The FT argued that a choice for "Leave" would favour "a pinched nationalism" and "marginalisation".
The editorial said there were "indisputable" rewards of membership of the 28-nation bloc.
"Since Britain joined the EU in 1973, real gross domestic product per head has grown faster than in France, Germany and Italy," it said.
"Membership of the single market has been a magnet for foreign direct investment, funding a bulging current account deficit and guaranteeing British jobs".
