A casket containing the relics of young French saint Therese of Lisieux will be displayed at St Andrew's Roman Catholic Church in Newcastle on September 30.

Thousands of pilgrims are expected to flock to the city for prayers and veneration and the church will stay open all night for the 20-hour visit.

Gerry Loughran, member of the organising committee at St Andrew's, told newsguardian.co.uk: "It's probably the most important religious event since the Pope was in the north."

There will be two Masses, one to be celebrated by Bishop Seamus Cunningham, former parish priest at Cullercoats and now Bishop of Hexham and Newcastle.

The relics of the young French nun, bone fragments in a sealed casket, will tour 23 places of worship in England between mid-September and mid-October, beginning in Portsmouth and ending in London.

After Newcastle, the relics will visit Carmel Convent in Darlington, the Anglican York Minster and Middlesbrough RC Cathedral.

"There is a lot going on nationally, but in Newcastle we have been having meetings for four months now and that work will go on until the day," Mr Loughran added.

"The casket will be coming in a vehicle, much like a converted hearse, the casket contains a few bones.

"Four people will be travelling with the relics, one will be a priest available to answer theological questions.

"We are currently in talks with the civic authorities and the police about possible road closures."

Pilgrim organisers stress that believers and non-believers alike are welcome at all the pilgrim stops.

Therese Martin was born in Normandy in 1873 and entered a convent of the Carmelite order of contemplative nuns at Lisieux as a teenager.

She never left the convent, living in total obscurity, yet became one of the headline saints of the modern world.

She was only 24 when she died but is the closest saint to today in terms of time.

Mother Teresa of Calcutta took her name from Therese; her photo was found on the bedside table of the fabled French chanteuse, Edith Piaf; and Princess Diana was known to light a candle before her statue.

Therese wanted to work as a missionary and in an effort to fulfil this failed desire, her relics have been on a pilgrim's journey for the last 15 years, visiting Iraq, Lebanon, Russia, Australia and the United States.

In Ireland, three-quarters of the population turned out to see the remains.

St Andrew's parish is keen to estimate the numbers likely to come to the church over the 20 hours and is asking visitors to advise of their intentions via e-mail at st.theresa.visit@hotmail.co.uk

There is also a dedicated page on the parish website www.st-andrews-worswick.org.uk/therese.html