a transient congregation caused in part by its location in London, a city which itself has a transient population, in particular a large student population who only reside in London during their studies, and that HTB is able to attract; and also in part by the fact that the Alpha course brings in a number of people to HTB who are either visiting the home of Alpha or have completed the course and then quickly move on to other churches or ministries. Services HTB conducts ten services each Sunday across the four sites. The family services include items aimed at children. The formal services feature traditional Church of England liturgy and a professional choir. The informal services centre on a longer period of contemporary worship with a longer talk and close in a reflective prayer mood which extends beyond the end of the service. The 4:30pm and 6:30pm services at HTB Onslow Square church extend this informal nature further as most of the congregation sit on carpet, whilst some couches, cushions and bean bags are also provided. These services are sometimes conducted in the round. Some services reuse the same talk and song list from a service earlier in the day. Other activities Another activity of HTB is its yearly church camp, named "Focus". This takes place over the course of a week in Somerley Estate, where typically 7,000 people attend and involve themselves in the many seminars, workshops and recreational activities. The size also attracts some prominent speakers to speak on issues affecting the church and society. Since 1985, HTB has been actively involved in a process called church planting whereby struggling churches in London are boosted by scores – sometimes hundreds – of people committing to move from HTB to the identified church for at least a year. This also involves at least one member of HTB's clergy similarly moving to the new church to help lead worship, form pastorates and run local Alpha courses. Over the years, nine churches have been planted in this way, including St Gabriel's, Cricklewood, with some of these churches going on to make church plants of their own. HTB also has thriving children's, youth and student ministries. Other activities HTB undertakes are services twice a year involving the large HTB choir – at Easter and Christmas – and several free classical concerts that utilise the church's pipe organ, refurbished in 2004, as