The BBC's Mike Wooldridge in Calcutta: "The sisters say they live under Mother Teresa's constant guidance"

Many said the physical absence of the Albanian-born Roman Catholic nun, who catered for Calcutta's poorest of the poor and was awarded the Nobel prize, would affect the order's working as well as its funds.

At the home for the dying in Calcutta much of the practical work is done by international volunteers

The order has about 4,000 nuns and hundreds of homes around the world.

But as the anniversary of her death on 5 September is commemorated, the Missionaries of Charity say nothing has changed - confounding predictions that without Mother Teresa the order may not survive.

'Mother is more powerful in heaven'

Sisters of Mother Teresa's order pledge to work for the poorest of the poor

Sister Nirmala, her Hindu-born successor, said if anything, the order was more vibrant, more powerful and more alive.

"The past year has been a year of deep sorrow, but at the same time a year of many graces," she said.

"Mother is praying for us. She is now more powerful in heaven."

Sixty-four-year-old Sister Nirmala has no illusions about replacing the Nobel prize winner.

"God is not asking me to be Mother Teresa. He is asking me to be Sister Nirmala," she said.

People were so touched

"It has been extraordinary after Mother's death. People were so touched that they gave huge amounts of money. Now that has stopped. But both the level of donations and recruitment are back to normal."

Sister Nirmala said that since Mother Teresa's death, the order had set up three new houses while 17 others would be opened by December in countries ranging from Australia to Cuba.

Some homes will be opened in India and Sri Lanka too.

Archbishop of Calcutta Henry D'Souza believes that the Vatican will beatify Mother Teresa

Henry D'Souza, the Catholic Archbishop of Calcutta whose diocese embraces some 50 parishes, was equally upbeat about the future.

"Mother Teresa's prominent value lies in that she is an indelible part of human history - she left behind not grief, but a holy memory of a person who sanctified the streets.

"That memory will live on. Therefore, the support to the Missionaries of Charity will continue."

Father Edward Le Jolly, a Jesuit priest who served as the order's spiritual adviser said it was pointless trying to compare Mother Teresa and Sister Nirmala.

"It is a heavy load to succeed a person as gifted as Mother Teresa. But one does not have to be her for the work to go on."

He said Sister Nirmala, unanimously elected Superior General for six years shortly before Mother Teresa's death, could take the order to new heights.

Le Jolly said the nuns and priests, who apart from the usual vows of poverty, chastity and obedience have to pledge to work for the poorest of the poor, would not change as the rules and constitution are rigid.

Possible sainthood

Sister Nirmala believes Mother Teresa will be canonised.

However, according to the Vatican any official canonisation will have to wait because under Vatican rules there has to be a five-year interval after a candidate's death. Beatification - a preliminary step to sainthood - could come sooner.

The legacy and memory of Mother Teresa remains strong in Calcutta despite some fundraising controversies and disagreements over erecting a statue.

Mother Teresa's final resting place - a simple grave in her order's spartan headquarters receives up to 200 visitors a day.

Shamim Akhtar, a Muslem, said his five-year-old son Amim was "getting his education" because of Mother Teresa.

"She was like an umbrella to everyone. My grandfather used to say she would come here twice every day to treat the sick. She removed the curse of tuberculosis."