At 10am on Sunday you cannot get into Holy Redeemer Church in Oval. A sea of people block the steps, and I am squashed between a young man with a bandanna and a diamond earring holding a small girl, and an olive-skinned woman arguing with her five-year-old son.

It is a typical crowd at the Mass for London’s Portuguese speakers from Madeira. About 200 attend each week. “We founded the Mass four years ago with four people,” says Manuel Eduardo Santos, 57, a sandwich-shop worker from Lisbon. When he moved to London in 1987, Portuguese speakers were scarce. Now their numbers have swelled by waves of migrants from Brazil and Madeira.

Just around the corner from Holy Redeemer is the vast, Victorian, red-brick church of St Anne’s, Vauxhall. Pushchairs line the aisles, pews are crammed with families from Colombia, Bolivia, Ecuador and Peru, all here for the weekly Spanish-language Mass. Their devotion is intense. “No one loves you like me,” they sing in Spanish at Communion time.

“Latin Catholicism is alive,” says the priest, Father Jesús Pérez Recio, one of the two Spanish chaplains assigned to serve London’s burgeoning Latin American community. Six Masses a weekend are provided for their 1,000 parishioners. Timing, however, is Latino rather than hora inglesa. “No one worries how long the Mass will last,” says Father Jesús. “If we start at 3pm who knows when we will end?”

When Mass draws to its close, Father Jesús gives the notices: the hours when Spanish-speaking lawyers will give free legal advice at the chaplaincy, who to contact to get your child into a London school, and of course, English classes.

This is the new face of Catholicism in Britain: global, exuberant, and bringing a fresh set of pastoral challenges to the Church.

“The Church is the first port of call for many Catholic migrants, the only institution they trust,” explains Francis Davis, director of the Von Hugel Research Institute in Cambridge.

Last year, the institute surveyed 1,000 Mass-going migrants in three London dioceses. “The new arrivals may be enthusiastic and their arrival is masking the freefall in Mass-going among English Catholics. But they are also poorer. Our survey found that 35 per cent of Catholics with the right to work here were being paid below the minimum wage.”

New arrivals from Africa, Asia, Eastern Europe and Latin America, at sea in a foreign culture and language, naturally gravitate to the Church for practical help, according to Bishop Patrick Lynch, head of the English Bishops’ Conference’s office for Migrants and Refugee policy.

“Globalisation and a more mobile labour market is bringing numbers of people to our parishes. They come with many spiritual and pastoral needs,” he says.

To address this, the Catholic Bishops’ Conference in England and Wales last week launched “Mission of the Church to Migrants in England and Wales”, a study paper suggesting a range of strategies to equip parishes to create “a ministry of welcome” for migrant parishioners. These include leaflets in different languages detailing how to access healthcare or the admissions policies of Catholic schools, the provision of English classes or interpreters, the collection of household items to help migrants set up homes.

So what exactly is the Church’s role?

“The Church has a responsibility to accompany migrants, to create a space where they feel safe, where they can come and talk. This is rooted in scriptural tradition: Jesus was from a migrant family and in the spread of Christianity, migration goes back to the Acts of the Apostles, says Bishop Lynch.” “Advocacy and advice” are what the Church can offer today. “We can point migrants towards the services available.”

A second challenge for the Church is how to nurture the vibrant faith of new arrivals yet integrate them into the local Catholic community, explains the Bishop. “Praying in a second language is not the same as praying in your first. How do you harness the giftedness of migrant communities and their diversity yet simultaneously create unity in the Church? “

In some parishes, integration is happening already. The Bristol parish of St Nicholas of Tolontino boasts a “one world” choir that regales parishioners every Sunday with hymns from the Democratic Republic of Congo, Kenya, Zimbabwe and Ghana. “God is really central to the lives of these people and they have a sense of celebration in the Mass which can be sometimes a bit lacking in our churches,” says Sister Liz Ferrie, a Daughter of Charity of St Vincent de Paul based at the parish. “They contribute a wealth of simple faith and trust in God.”

Some see this vibrant faith as a sign of hope for the future. María Jacinta Guindano offers catechesis in Spanish to Latino teenagers, some of whom have arrived only months ago in the UK. “It is a culture shock for them,” she explains. “British teenagers tend not to depend on their families the way Latin Americans do, but their faith gives Latin Americans a sense of security.”

However, Monsignor Tadeusz Kukla, head of the mission to Polish Catholics in the UK, gives warning that secularism can exert an equally strong influence. “Only about 10 per cent of the young Polish people here attend church, they are so preoccupied with making money that they have very limited time for church, and will lapse within a few months if we don’t attend to them. The whole atmosphere here is secular.”

For him, this is an argument for Masses to be provided first in Polish before attempts are made to integrate young Poles into English-speaking parishes, a point on which Cardinal Murphy-O’Connor has led discussion with the Catholic Church in Poland.

In a climate where migrants tend to be assessed in purely economic terms, the Church exalts their dignity, regardless of their legal status.

“They are committed to their values and communities and want to contribute to the social fabric of society,” says Bishop Lynch. “It’s migrants who are running the NHS at ground level now.”