Foreign aid will be spent in Britain’s “national interest” to boost post-Brexit trade, the International Development Secretary has vowed.

Priti Patel said leaving the EU would allow the Government to reclaim billions of pounds of annual aid funding that is currently diverted via Brussels.

It could then be used, not only for “humanitarian” work, but also for “prosperity Britain post-Brexit, on trade and economic development,” she told the Commons International Development Committee.

“There are a whole raft of opportunities there where we can use that money for our national interest, or Global Britain’s interest, as well as helping to alleviate poverty around the world,” Ms Patel said.

The comments were criticised by the Liberal Democrats, who accused Ms Patel of “politically-motivated attacks based on zero evidence”, because EU aid work had been shown to be of “incredibly good value”.

“The primary purpose of development aid should be lifting the poorest people in the world out of poverty, not serving the government’s post-Brexit trade strategy,” said Baroness Sheehan, the party’s spokeswoman.

Ms Patel first floated her intention to use some of the £13.3bn annual overseas aid budget to help secure post-Brexit trade deals a year ago. It could be a tool to win badly-needed allies in the World Trade Organisation (WTO), she suggested.

However, the International Development Secretary softened her language earlier this year, when she won a Cabinet battle to save the legal commitment to spend 0.7 per cent of national income on aid.

A 1,700-word statement, issued to Parliament in April, spoke of the “national interest” only in terms of preventing crisis from poverty overseas reaching “our doorstep”.

Theresa May toyed with with axing the 0.7 per cent pledge, inherited from David Cameron, but eventually faced down right-wingers in her party.

But, giving evidence on her department’s priorities, Ms Patel – a prominent Leave campaigner – coined the “Global Britain” phrase normally used in arguments for trading opportunities outside the EU.

She explained that after Brexit in March 2019, aid money would no longer be sent “unconditionally” to Brussels, with little scrutiny.

“There isn’t much oversight and transparency, and accountability in terms of how that money is spent,” Ms Patel said.

“I would like much of that money to remain with us, so that we can see how that money we now give to the EU comes back to us, and then obviously we can determine how it is spent.”

She added: “If it is in a refugee camp, for example, in Jordan or Bangladesh – that kind of work will continue.

“But it will be a very, very different way of working to what we have now, where we just give a chunk of money over to the European Commission which we don’t have any oversight over.”

A recent law gives Ms Patel’s department the power to quadruple the amount of funding funnelled through the CDC Group – its private equity arm – to £6bn.