Over the last six years, the Barna group in the US has been collecting data about the "churchless" – those who used to go to church, but now no longer do so. The findings are explained in a new book by George Barna and David Kinnaman, called Churchless. 

The pair say the research, undertaken between 2008 and 2014, shows that while more people now believe religion makes "little positive contribution on society", more than half are searching for something spiritual that's "better than they [have] experienced to date." 

A third of those identified as churchless said they have an "active relationship with God". 

A search for genuine answers to the questions that living in the 21st century brings lead to many of this group leaving. To stop this flow away from the Church, mentors should be trained and efforts made to provide thoughtful responses to these doubts and questions, Future First suggests. 

In its analysis of the research, Future First identifies the need to address faith's apparent conflict with science, the dislike of the Church's rigidity on sexuality and the unhappiness with Christianity's claim to exclusiveness. 

In the UK, 44 per cent of adults polled in 2014 said they used to attend church, but no longer do so. 

In the US, where the research was conducted, more than half of those born between 1984 and 2002 are unchurched. 

The unchurched are likely to be younger people, under the age of 50. In fact, the younger you are the more likely it is that you will never have been to church. 

It's research like this that prompted the Evangelical Alliance to set up threads, a community of those in their 20s and 30s who may have become disillusioned with Church somewhere along the way, when things happened in their life that the Church was silent on. 

At threadsUK.com, the threads community discuss divorce, debt, depression and more, with new posts each day examining issues facing this age group – whose attendance has halved in the UK Church in little more than two decades. 

At The Pursuit last month, a new festival established by Spring Harvest for millennials, threads hosted a secret doubt garden, designed to encourage honest discussion with peers about doubt. More than 40 people engaged, making flowers and leaves in the craft area that they wrote their own personal doubts on, which were then pinned up to get these questions out in the open. 

Many said it was the first time they'd been able to properly air and discuss their doubts in a safe environment. While reviewing the festival, three people named the secret doubt garden as their "breakthrough moment" during the festival. 

If you are able to support threads, you will enable us to reach out to those young people who might be far away from church: through the online community and through real-life, face-to-face events. 

Supporting threads is easy. For as little as £3 a month, you play your part in ensuring this generation is no longer missing. Support threads here. Thank you.