The new Department for Exiting the European Union (DExEU) has plenty of "bright young civil servants" but not "much grey hair yet", Brexit secretary David Davis has said.
DExEU was established in July as Theresa May implemented a shake-up of Whitehall following Britain's vote to leave the European Union. It currently has around 200 staff based in London, including five secondees from the private sector, and is drawing on support from more than 100 officials in Brussels.
Ministers have said they want DExEU to be staffed by the "brightest and best" from across the civil service, while the department's permanent secretary Olly Robbins has said it is aiming to "stay small" and coordinate work across government.
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Davis, the cabinet minister put in charge of the department, told members of the House of Lords EU committee this week that his ministry was "actually quite tiny" at present but had "quadrupled" in size over the past eight weeks.
"It'll probably double again in size but it'll still be very small by the standards of Whitehall," he said. "Once we get to that sort of size we're going to be looking to outsiders. I've got a lot of very bright young civil servants – I haven't got that much grey hair yet, which I may have to find outside."
Davis said the department was working on the "sexiest area of politics" at the moment, meaning it received a deluge of submissions offering advice on Brexit.
And he revealed that DExEU had asked "pretty much every department" across government to "go out and talk to its stakeholders" about the risks and opportunities presented by Britain's withdrawal from the EU while the government formulates its negotiating position.
The consultation process would, he said, allow departments to size up the pros and cons of specific policy changes before DExEU begins some "some quite quantitative assessment of what we think the advantages and disadvantages are".
Davis admitted he had been "ribbed" in parliament last week for saying the referendum vote to leave the EU was "a national instruction" that DExEU would try to interpret "in the national interest".
But he said: "We need to take an empirical approach, the purpose of this is not to damage the national interest or damage the economic interest – it's just the reverse."
DExEU would not, he said, "be saying an awful lot" in public before Article 50 – the formal mechanism by which the UK triggers EU exit talks – is triggered, with the minister saying he did not want to give a "running commentary" on the department's work.
Asked whether he would draw on the advice of former cabinet secretaries and top civil servants in the House of Lords, Davis replied: "I do pay great attention to my elders and betters."
The Brexit secretary will face a fresh round of questioning in parliament today when he appears before the Foreign Affairs Committee.