A recording reveals that the British PM said it was time the UK took a lead in Europe, The Guardian reports
Theresa May privately warned a month before the EU referendum that companies would leave the UK if the country voted for Brexit, according to a report in The Guardian.
The paper claims a recording of her remarks to bankers at Goldman Sachs reveals that despite her more guarded public comments she had concerns about Britain leaving the European Union.
Speaking on 26 May, the then home secretary appeared to go further than her public remarks to explain more clearly the economic benefits of staying in the EU.
It is reported she told staff it was time the UK took a lead in Europe and that she hoped voters would look to the future rather than the past.
In an hour-long session, she also worried about the effect of Brexit on the British economy, The Guardian says.
"I think the economic arguments are clear," she said. "I think being part of a 500-million trading bloc is significant for us. I think that one of the issues is that a lot of people will invest here in the UK because it is the UK in Europe.
"If we were not in Europe, I think there would be firms and companies who would be looking to say, do they need to develop a mainland Europe presence rather than a UK presence? So I think there are definite benefits for us in economic terms."
Although her office insists Mrs May's Goldman Sachs remarks were entirely consistent with her public statements, they strike a different tone from her comments about Brexit since becoming British prime minister.
"Maximum freedom to trade and operate in the single market"
At the Conservative party conference earlier this month, Mrs May said that she wanted to prioritise reducing immigration over being part of the single market.
In her speech, she said British companies needed the "maximum freedom to trade and operate in the single market" but not at the expense of "giving up control of immigration again" or accepting the jurisdiction of judges in Luxembourg.
At Goldman Sachs, she also said she was convinced Britain's security was best served by remaining in Europe because of tools such as the European arrest warrant and information-sharing between the police and intelligence agencies.
"There are definitely things we can do as members of the European Union that I think keep us more safe," she is reported as saying.
The disclosure will surprise many leading Remain campaigners, who have accused Mrs May of behaving like a "submarine" during the EU referendum and offering only lukewarm support for the campaign.
In April, she gave a speech in which she set out some of the reasons for staying in the EU, warning that it could have an impact on the development of the single market for the rest of the EU if the UK left.
But her comments at the Goldman Sachs event a month later go further in warning about the dangers to the British economy from businesses relocating to continental Europe.
Responding to The Guardian's report, a Downing Street spokesman said: "Britain made a clear choice to vote to leave the EU and this Government is determined to make a success of the fresh opportunities it presents.
"David Davis made very clear in the House of Commons last week the importance the government places on financial services across the UK in the negotiation to come, as has the Chancellor in recent weeks.
"We want a smooth and orderly exit from the European Union, which would be in the interests of both Britain and the EU."
But Liberal Democrat leader Tim Farron said: "It is disappointing that Theresa May lacked the political courage to warn the British public as she did a group of bankers in private about the devastating economic effects of Brexit.
"But far more disappointing is that now she is supposedly in charge, she is blithely ignoring her own dire warnings and is prepared to inflict an act of monumental self-harm on the UK economy by pulling Britain out of the Single Market."