"Speaking to refugees has made me see the trauma people face could be eased if Europe would sufficiently invest in the hundreds of thousands who are in need."
He said he had wanted to take a delegation from the United Synagogue to see the work the Anglo-Jewish community has already helped to fund, and show refugees that the community "is serious about responding to the crisis in a big way".
He said: “I'm enormously proud of the response of the community.
"Thanks to WJR, our community is helping to provide life saving initiatives.
"I connected today with refugees from Syria, Libya, Afghanistan, and Eritrea who are all fleeing from persecution and danger.
"Every human soul is precious and it is central to our Jewish ethos for us to reach out and assist whoever we can."
He added: "The entire purpose of this trip is the follow-up.
"Together we will share our experiences and reflections with the community when we get back.
"I would like to encourage the United Synagogue and the entire community to engage in a wide range of initiatives to help refugees.
"We should not allow this plight to fall off the radar. It is an ongoing crisis and will need an ongoing response."
The trip, organised by WJR, took place amid high security as Rabbi Mirvis and his colleagues arrived in the Greek town of Idomeni.
Details had been a closely-guarded secret as the plans to send the rabbis to the town were formed over the past fortnight.
Rabbi Danny Bergson, of Pinner United Synagogue, said he "wasn't sure what to expect".
"There was a lot of uncertainty. No amount of briefing could prepare me for the moving and inspiring experience of seeing people at their most vulnerable.
"To hear people's deepest fears and uncertainties was overwhelming.
"Despite the difficult circumstances people found themselves in, I was moved by their sheer strength and optimism."
Also accompanying the Chief Rabbi was Rabbi David Mason, of Muswell Hill United Synagogue and St John's Wood United Synagogue's Dayan Binstock.
Rabbi Mason said he felt privileged to witness "something that is a clear crisis of humanity".
He said: "I'm very eager to work with my rabbinic colleagues to ensure that we build appropriate ways to act in this issue."
More than £700,000 has been raised through WJR's Syria crisis appeal, the second highest total for a fund in the charity's history.
In Greece, Rabbi Mirvis and his delegation saw how WJR is providing medical care and food distribution for refugees crossing into FYR Macedonia.
Rabbi Binstock said he was amazed by the "dedication of people who come to volunteer" and the "efficiency of the camp".
For Rabbi Boruch Boudilovsky, from Borehamwood and Elstree United Synagogue, getting a chance to speak to refugees and "understand their fears and share their hopes made a deep impression".
JC reporter Rosa meets some of the refugees at the camp with the Chief Rabbi
He added: "Seeing a three-year-old girl being treated by a doctor thanks to the support of WJR made me proud of our community."
WJR's chief executive, Paul Anticoni, said: "The Jewish community has responded with extraordinary compassion to Europe’s greatest refugee crisis since World War Two.
"The Chief Rabbi’s engagement on the ground in Greece is a reminder of our willingness to not only assist those within our community, but to reach beyond as well, with the expertise and compassion synonymous with all of World Jewish Relief's international work.
"He has witnessed how the British Jewish community, many inspired by personal refugee stories, has provided vital medical supplies, shelter, food and education to thousands fleeing war and persecution."
Money raised by British Jews has already helped Syrian children in Turkey, who have escaped the conflict, by giving them warm winter clothing, books and school equipment.
JC reporter Rosa Doherty talks about her visit to Idomeni refugee camp and the stories of the people she met there
