This year's Thy Kingdom Come will focus on praying for Christians who have drifted away from church during the pandemic, and "those who've just been tasting".
The ecumenical prayer movement is the initiative of the Archbishops of Canterbury and York, but many denominations are involved, from the Redeemed Christian Church of God, to The Salvation Army, Catholic Church, Methodist Church and Coptic Orthodox Church.
It has grown into a global movement in the five years since it was first launched, with a presence in 90 per cent of countries around the world last year.
It will take place this year from 13 to 23 May, the period between Ascension Day and Pentecost Sunday. In past years it has taken place in Trafalgar Square, but was held online last year due to the pandemic and will be held virtually again this time round.
In a video message to the online launch event on Tuesday, Archbishop of Canterbury Justin Welby explained the decision to focus prayers on newcomers and those drifting from church.
"This year, Thy Kingdom Come will look different - it must look different - because of all that we've been through over the last 12 months," he said.
"It's been a year that none of us will ever forget. We've all had to learn new ways of connecting and one of those for which we're hugely grateful is through technology.
"All of us have become more tech-savvy - even I have become more tech-savvy.
"For most of us, to some degree there's something left out, and a number of people have drifted away from participation in worship because they simply can't get with the whole thing of taking part while looking at someone on a screen.
"But there's been some incredible blessings. One is that huge numbers of people have joined in because they can do so and just taste what Christian worship is about without physically having to go through a door."
He asked Christians to pray that those who have attended church for the first time during the pandemic would "see the wonder and the love of Christ" and that "as they draw closer to the Church they [would] see also the remarkable things the Church has been doing, because as well as all the online stuff, the Church has been reaching out physically right around the world".
"It's been extraordinary, with foodbanks and debt counselling, and [keeping people] company and ringing people up and caring for people and looking after them in the most phenomenal way," he said.
"The heart of it is beautifully simple, which is to pray."
New resources for 2021 will include an 11-part family-friendly animation series, video reflections from Bear Grylls, the Bishop of Dover Rose Hudson-Wilkin, Archbishop Angaelos, and a prayer journal penned by the Archbishop of York, Stephen Cottrell.
To find out more about the resources and event, visit www.ThyKingdomCome.global
