Mr Lammy told the i podcast Labour’s Plan For Power that the EU will be Labour’s “number one priority” in foreign affairs.
He said: “It’s our number one priority because it’s our backyard.
“It’s our number one priority because there is war in Europe and because I believe our future prosperity and security is predicated on good relationships with our European partners.”
The MP for Tottenham added that if Labour were to win the election, there would be “a tonal shift” in UK-EU relations with a move to return to more regular talks between the governmental powers.
He also said he believed Britons would find it “extraordinary” that the UK Government does not sit down for talks with the European Union “every four months or every six months” to go over issues relevant to both parties.
“We need to get back to that,” he said.
The shadow minister also told the i that a defence security pact with the EU would be high on the agenda.
“(Boris Johnson) rejected a defence-security pact with the European Union, and we said that we think a security pact is fundamental,” Mr Lammy said.
“I think war in Europe demonstrates that.”
When speaking of the conflict in Ukraine, Mr Lammy said any security pact with the EU would “be cast as wide as possible” to include “security issues in relation to migration”.
But Mr Lammy stopped short of a Labour pledge to return to the EU, pointing out that there would be no contemplation of broaching the matter in the current political cycle.
Instead, he insisted that his focus as foreign secretary would be to work in the national interests of both Leave and Remain voters.
But he did not rule out a return to the EU down the track, notable after recent polling suggested the British public has an increasing regret about Brexit.
