I had read many articles about the antisemitism in France and I watched a number of the YouTube videos of the recent attacks. But it wasn't until I joined a cross-party delegation of MPs to Paris with the All-Party Parliamentary Group Against Antisemitism (APPG) that I understood how grave the situation is.

A chance conversation with a Jewish Parisian businessman on the outbound journey set the tone. He told me that the situation has become so bad you either have to have enough money to live in a safe area or make aliyah.

The numbers speak for themselves. Although Jews constitute just one per cent of French society, 40 per cent of the racist crimes perpetrated in France last year were against them.

The problem is so complex it has perplexed political leaders and others. We were told that antisemitism stemmed from the poor economic situation in France (and the success of the far-right in capitalising on resulting insecurities); a general disillusionment with politics; the capacity of religious extremists to exploit French secularism to their benefit; the Middle East conflict, and the strength of the populist movement built on a hybrid of right-tinged old-style antisemitism merged with a left-tinged new antisemitism.

Whatever its source, the effects are devastating. CRIF, the body which represents French Jewry, told us about the mass exodus of Jews from France and an exponential increase in verbal and physical antisemitic incidents.

We were told by students that it is not safe to wear a kippah and talk about Jewish matters on the streets or on public transport. People are regularly abused and parents are moving their children out of state education into private Jewish schools.

In general, French politicians have responded forcefully, at least in words. Statements have been issued by ministers and security has been significantly increased. Parliamentarians we met told us starkly that France is experiencing a return to the antisemitism of the 1930s. François Pupponi, mayor of the Paris suburb of Sarcelles, said some of his constituents are expressing their antisemitism quite openly.

However, the government officials we met were keen to qualify that there is not a "mass antisemitism" in France but rather that the antisemitic actions of a few have been amplified through social media.

They were also eager to highlight their action against the antisemitic comedian, Dieudonné M'bala, and their convening of a cross-government task force to counter antisemitism.

But the efficacy of government programmes was challenged by others we spoke to from civil society organisations and within the Jewish community.

This summer was particularly frightening. In the words of one Jewish student there was an "urban revolt" and "near civil war" in Paris. We were told that police in Sarcelles informed the Jewish community that if rioters passed their lines, they would have to fend for themselves.

This has led to the community fearing that the state is impotent. While some protests were banned, the authorities were said to have been caught off-guard.

It is important, of course, to reflect on what we learned in the context of the UK. Fortunately, we have set the standard for combating hatred against Jews. Most recently, my colleague, John Mann MP, the chair of the APPG, announced we will be producing a report on the antisemitism emanating from the Middle East conflict which we saw in the UK over the summer. Our visit to France will help in building the recommendations for this report.

As a Jew in Britain, I shared the anguish felt by the community during July and August. Conflicts divide people and in the case of Israel-Palestine the anger was palpable. However strong people's passions, we cannot allow the UK to become a staging ground for antisemitic retribution.

At our final meeting in Paris we were told an old "joke" which had gained new relevance. "There were two types of Jews in Poland during the 1930s and '40s - the optimists and the pessimists. The pessimists," we were told, "ended up in New York".

We must not let the scourge of antisemitism blight our national debate, nor tear the fabric of our society. Colleagues and I want to make sure that Jews in Britain never fear being the optimists.

Luciana Berger is member of Parliament for Liverpool Wavertree and a member of the APPG Against Antisemitism