Twenty thousand people are set to return to church with a friend this weekend as part of a major co-ordinated effort by the Church of England to pack the pews in around 2,000 participating churches.

Around 200,000 invitations are expected to have been delivered to curious non-churchgoers by the time of Back to Church Sunday on 30 September

On Monday, bishops from Exeter to Peterborough and Manchester to Oxford - representing half of the Church of England's dioceses - put their campaigns into action by taking to the skies in planes or hot air balloons, launching podcasts and unveiling advertising campaigns.

The unprecedented co-ordinated activity aims to encourage churchgoers to invite a friend, who has stopped going for whatever reason, 'back to church'.

The Archbishop of Canterbury, Dr Rowan Williams, has personally backed the initiative, commenting: "Millions of people remember and love church, but perhaps they've just drifted away for a while. Back to Church Sunday is a chance for church people to invite a friend to come back and see what they've been missing, and to help them reconnect with God in special services of welcome across England."

In anticipation, local churches have ordered Back to Church Sunday boxes, sponsored by Traidcraft, packed with special invitations, posters and T-shirts, and have been preparing special 'open day' style services and improving their welcome techniques at summer workshops.

The idea builds on research that recently revealed three million people (six per cent of the adult population) would come back to church if they received a personal invitation.

This type of opportunity for churches formed the basis for the idea of Back to Church Sunday, which began in the Diocese of Manchester in 2004 and has been growing steadily ever since - with more dioceses taking part every year.

Organisers predict that this year's event will see 20,000 people return to church this Sunday, based on an average figure of ten people returning to each church that has previously taken part in the event.

Church attendance figures have been relatively stable since 2000, with weekly and monthly attendance falling by one per cent or less between 2004 and 2005. This followed two years in which the numbers increased or held steady.

The latest figures suggest that around 1.7 million people attend Church of England church and cathedral worship each month, while around 1.2 million attend services each week - on Sunday or during the week - and just under one million each Sunday.

With just six days to go until Back to Church Sunday, the Bishop of Southwell & Nottingham, the Rt Rev George Cassidy, will blast off in a hot air balloon from the centre of Nottingham today while the Bishop of Sherwood, the Rt Rev Tony Porter, will simultaneously take to the sky in a light aircraft from Nottingham to Blyth, trailing a banner promoting the event.

The sky will also be alive with the message of Back to Church Sunday across London, Essex, Derbyshire, Northamptonshire and Manchester, when hundreds of balloons will be released to raise awareness of the event.

The Bishop of Derby, the Rt Rev Alastair Redfern, will help children from local schools in Mickleover to release balloons this afternoon; while in Northampton, the Bishop of Brixworth, the Rt Rev Frank White, will launch 190 balloons to represent the number of churches taking part in the initiative across the Diocese of Peterborough.

Simultaneously, the Bishop of Peterborough, the Rt Rev Ian Cundy, will set off the same number of balloons from the city centre of Peterborough with invitations back to church attached to each.

In Manchester, the Bishop of Manchester, the Rt Rev Nigel McCulloch, will also release dozens of multi-coloured balloons with invitation tags attached.

The Mayor of Chelmsford, Cllr David Lee, and children from Chelmsford Cathedral School will help to launch a hundred helium balloons outside Chelmsford Cathedral, while the Mayor of Southend, Cllr Daphne White, and the Bishop of Bradwell, Rt Rev Laurie Green, will launch balloons from Victoria Plaza, Southend.

In south London, the Bishop of Southwark, the Rt Rev Tom Butler, will address the congregation of All Saints, West Dulwich, and children from local schools will be on hand to launch balloons. The whole congregation of All Saints went 'back to church' in April 2006, six years after the church had been totally gutted by a fire.

Canon Paul Bayes, the Church of England's National Mission and Evangelism Adviser, believes the event is a key opportunity for churches: "The most important thing about Back to Church Sunday is ensuring that those returning to church get a truly warm welcome.

"Things like the length of services, the hymns and songs we sing and even the way we give out notices can all have an impact on the welcome people feel. It's also critical that churches think though what they can offer people who have made that brave step to come back.

"I hope many churches will be setting up an informal course explaining the Christian faith, or perhaps holding special lunches over the next weeks for returning worshippers to meet each other."

Back to Church Sunday is being run in churches across the dioceses of Bath & Wells, Birmingham, Blackburn, Chelmsford, Chester, Coventry, Derby, Ely, Exeter, Guildford, Lichfield, Manchester, Norwich, Oxford, Peterborough, Ripon and Leeds, Rochester, Southwark, Southwell & Nottingham and Wakefield.

The Bishop of Lichfield, the Rt Rev Jonathan Gledhill, will launch a new weeklong radio and poster advertising campaign for the region today when he unveils a giant billboard poster in Cannock. The advertising campaign will also feature roadside posters in Hanley, Oakengates and Wolverhampton, and radio adverts in Wolverhampton, Shropshire, the Black Country and Staffordshire.

The Bishop of Birmingham, the Rt Rev David Urquhart, will be swapping his mitre for a motorbike helmet as he spends today dashing round the region visiting 13 parishes in one day and popping in on clergy, nurseries and schools on his travels.

Bishop Urquhart said: "People can get out of the habit of going to church but I am sure that church has a lot to offer people in 21st Century Britain - especially those considering questions about the purpose and meaning of life."

The new Bishop of Oxford, the Rt Rev John Pritchard, earlier appealed to people in the Thames Valley who have stopped coming to church to tell him why - and to let him know what might bring them back again through a special website, www.tellbishopjohn.com.

He is now looking through the responses to see what action the Church could take and will be creating a podcast to reflect on his findings.

The Bishop of Exeter, the Rt Revd Michael Langrish, will be talking to commuters as they make their way past Exeter Cathedral to work this morning to find out about their experiences of church, and - if they used to attend regularly but have now stopped - what would encourage them to think about going back.