For about a decade I’ve been working to strengthen Christian-Jewish friendship in the UK at a grassroots level. I’ve spoken to ministries and prayer groups in places like Warrington, Wigan, Fareham and Liskeard.

My work is principally with that section of the church in the UK which describes itself as Christian Zionist.

I’ve seen at first hand their love for the Holy Land and Hebrew scripture, and their practical support by way of visits to Israel, generous charity giving and support for advocacy on behalf of Israel.

They want to stand with the Jewish community in the face of growing antisemitism and, in turn, I believe the Jewish community could be doing more to protest against the persecution of Christians in so many parts of the world.

The basis for friendship and for shared action is strong.

Yet the question I am asked most by my Jewish friends and colleagues about my work is, “what is their agenda?”

In a hostile world, are Jews ever justified in being suspicious of their Christian friends?

The answer I’m afraid has to be yes — but a qualified yes.

It may come as a shock to learn that 15 or so registered charities in the UK exist exclusively to convert Jews to Christianity, or it is a significant part of their purpose. And together they have raised more than £35m in the past five years.

Or to put it another way, that is more than six times the charitable income of the Board of Deputies over the same period. It also dwarfs the resources available to the Council of Christians and Jews — which was established to put Jewish-Christian relations on a new footing of respect and trust.

What are the likes of Jews for Jesus — and about a dozen organisations like them — doing with all the money they collect?

To read through the online accounts and reports of these missionary organisations is to be confronted by the mundane, the absurd and, occasionally, the faintly disturbing.

Activities go well beyond the wearisome handing out of tracts at Tube stations and door-to-door evangelism in largely Jewish districts.

A health food shop in Temple Fortune — run by “Binyamin Ministries” — provides an unsettling opportunity to reach Jews and others with the Gospel.

A charity called Messianic Testimony proudly boasts that their missionaries are active in care homes for the elderly and that one of their staff sings in a North London Jewish choir. These kinds of activities may be well-intentioned but are likely to be greeted with concern by most Jews.

Much of the funding by UK ministries is directed at impoverished and isolated Jewish communities overseas — missionaries and New Testaments are dispatched to Ethiopia, Eastern Europe and the Former Soviet Union.

One charity called Eurovision (nothing to do with the song contest), with an annual budget of over £2m, says it focuses an increasing amount of its energies on converting Holocaust survivors in Israel — and claims significant success.

And in the 21st century large sums are invested in social media platforms to reach younger Jewish audiences with the Gospel.

Surprisingly, perhaps, much activity by these organisations takes place in churches. For instance, CMJ (previously known as the Church Ministry Amongst Jewish People) teaches the Hebrew roots of the Christian faith to fellow Christians. But the missionary organisations also encourage and equip ordinary Christians to reach out to Jewish colleagues, neighbours and friends.

The idea is that the initial approach should be by a friend, then professional missionaries can step in if the Jewish person shows any interest.

It is important to point out that not all Christians are engaged in such activities.

The Roman Catholic church has officially abandoned any mission to convert the Jews. And those in the liberal mainstream denominations usually want nothing to do with it.

But even the established Church of England continues to have an officially recognised missionary arm “advancing the Gospel to the Jewish people”: the CMJ referred to above. With 13 employees and 60 volunteers, CMJ has recently increased its expenditure to evangelise the British Jewish community.

They have strengthened their community-based missionary team, whose activities range from manning street stalls in Stamford Hill to engaging with Jews at New Age festivals.

The activity is overwhelmingly generated by those evangelical Christians who describe themselves as born-again Bible believers, and who also profess great love for Israel and the Jewish people .

What motivates them?

These Christians take seriously the New Testament mandate to export the Gospel of Christ to the four corners of the Earth. The great commission from Jesus himself is to evangelise all nations.

But that doesn’t quite explain the obsession with Jews. Particularly at a time when a huge number of our fellow UK citizens have never opened a Bible in their lives, why target a community that still boasts a strong measure of its own faith?

The New Testament declares, “to the Jew first”.

The idea that Jesus was born and died “king of the Jews” while his own people reject him is a cause of anguish to many Christians — and perhaps gives rise to a measure of self-doubt. Why are those who learn and teach the Bible in its original language not convinced — as Christians are — that scripture screams out Jesus on almost every page?

Every Jew who converts to Christianity is therefore a source of self-justification. Their testimonies — the story of what brought them to Jesus — are much prized on YouTube.

And it’s about more than any one individual Jew.

The Apostle Paul asserts Jesus has established the “new man” – that the previous division between Jews and Gentiles was done away with at the Cross. The fact that 2,000 years later this is manifestly untrue — and Jews retain their own separate faith — is both a tragedy and a challenge (which many Christians attribute to failings in the Church rather than the Jews).

Paul said that he would rather himself end up in the flames of hell — the destination of all non-Christians — if only the Jews could be saved by Christ.

Some evangelicals also believe that Jewish people converting is a pre-condition to an imminent second coming. The people of Jerusalem must be ready to welcome and worship the Christian Messiah when he returns.

Therefore, many of the UK based ministries fund and support “Messianic communities” in Israel which accept Christian doctrine on the basis that the salvation of the entire world will come from converted Jews.

Whatever the theological or psychological basis for it, the money appears to keep rolling in.

What is the outcome of all this expenditure and effort? In my travels I come across Jews by birth who are now “born-again” as Christians. Most, I discover, have had tenuous connections with Judaism and few of the missionary organisations give out precise information of the number of baptisms achieved.

Carefully reading their annual reports, there are occasional acknowledgments of frustrating lack of progress; waning support from Christians; and in CMJ’s case, the difficulty of getting high ranking Anglicans to officially endorse their activities.

Even though the impact may be only conversion in the hundreds, such work does poison Jewish-Christian relations.

Targeted and at times aggressive or underhand proselytism cannot co-exist with friendship - and thankfully many of our Christian friends are aware of it.

Organisations such as Christian Friends of Israel, International Christian Embassy of Jerusalem, Project Ebenezer and Christians United for Israel do not engage in proselytism. In some cases they have even signed non-proselytism agreements so that they can support the Jewish Agency promote aliyah to Israel.

And for that decision, they often face fierce criticism from other Christians - and they deserve our encouragement and support.

Steven Jaffe is director of the Shalom Initiative