The long-term decline in church congregants in the UK has been slowed by people of ethnic minorities, according to a survey.

Christian Research, a religious think tank, found that a third of churches, especially those with predominantly black congregations, are growing.

Churches in England have been in long-term decline since the 1950s, with an estimated one million people giving up regular churchgoing in the 1990s alone. Figures show a fall of 500,000 drop in typical Sunday congregations since the last comparable research in 1998.

Overall, congregations are generally older than the average age of the population.

However, the decline has been slowed as Britain has become more ethnically diverse, based on an extensive census of congregations in 2005.

Worshippers from black communities now outnumber white churchgoers in London. Many black Christians have formed their own churches while African communities have been introducing their own particular institutions into the UK.

Some of these churches have become the most successful in the UK with weekend congregations sometimes topping 1,000.

While the growth of black churches has been recognised for some time, the figures show that it has been significant enough to affect overall church attendance in the UK.

Elsewhere, the Roman Catholic church may start growing if migrant workers continue to arrive from Eastern European nations such as Poland.

Researchers at the think-tank also found that more than a third of churches were now growing compared with just a fifth in 1998. There had also been a slight increase in the number of churches describing their numbers as stable.

A quarter of churches which reported falling numbers in the 1990s were now saying their congregations were growing.

However, declining churches are still losing more people than the growing churches are gaining, suggests the study.

Dr Peter Brierley of Christian Research said: "It is a great joy to have some good news at last. Although the overall numbers are still going down there are many signs of hope in the statistics.

"It is important that church leaders, both nationally and locally, pick up on these positive things, learn from those who are doing well, and build for the future.

"If that happens we could see the church in this country once again having a major impact on our nation."

The Reverend Katei Kirby of the African and Caribbean Evangelical Alliance welcomed the figures.

"While it is significant to see the increase in the numbers of Black people attending church in England, it is equally important to see where they are attending in the independent and Pentecostal sectors as well as in the nominal or mainstream denominations," said the Rev Kirby.

"I think that this will continue to have a major impact on the picture of church attendance trends in the future."