Roman Catholicism is growing by leaps and bounds in England – mostly because of Eastern European immigration. The question is, will the traditionally reticent English institutional church be up to the challenge of nurturing the vigorous faith, a faith given even deeper resonance by the urgency and need of the immigrant experience?

The Catholic Church is the first port of call for thousands when they find themselves in difficulty, with up to 95 per cent from countries such as Poland being practising Catholics. Some churches find that they are being used as both job centres and social welfare offices. Most of the migrants settle in London, where some parishes are putting on Sunday Masses from 8am to 8pm to cope, the report, carried out by the Von Hugel Institute at Cambridge, found.

The report calls on the Catholic hierarchy to act urgently to help the migrants and their hard-pressed clergy by investing thousands of pounds in new resources.

Officially the Church is welcoming the migrants, but nearly all bishops and clergy have been taken by surprise by the influx, which took off last year and has yet to be reflected in official Mass attendance and membership figures.

But they acknowledge that the immigration is changingthe face of Catholicism across Britain.

From being an Irish-English church in a mindset of managing steady decline, the Church has within the space of 12 months found itself having to countenance an unprecedented expansion and change in its ethnic make-up.

Figures for 2005 show that there are 4.2 million Catholics in England and Wales, under one fifth the 25 million baptised Anglicans and double the number of Muslims.

But the real Mass attendance figure is higher by many hundreds of thousands. Precise numbers are impossible to obtain because of the irregular status of so many of the migrants, who prefer to keep a low profile. Some would only talk to researchers for the report through their priests, and some clergy even refusedto be interviewed for fear of attracting attention.

But the head of the Polish vicariate told The Timesthat the number of Poles in London had doubled since their country’s EU accession to at least 600,000. According to the report, the number recorded attending Mass represents a fraction of the total number of baptised Catholic migrants now in London.