A man has been arrested on suspicion of rape at Holy Trinity Brompton's Focus Festival.
The man was arrested on Wednesday and is being questioned by Hampshire Police.
The festival at the Somerley Estate on the Hampshire-Dorset border attracts thousands of mainly younger people and is badged as 'a week of teaching, worship and community for HTB and associated churches'. HTB is associated with the Alpha Course popularised by Nicky Gumbel.
This year the gathering was addressed by the Bishop of London, Dame Sarah Mullalley, and RT Kendall.
Participants saw police on site as festival-goers were packing up to leave on Tuesday.
A police spokesman told Premier: ' A police spokesman said: 'We were called at 05.06am on August 1 to a report of a 21-year-old woman being sexually assaulted at the Focus Festival which was being held at the Somerley Estate, north of Ringwood at some point between 1.30 am and 2 am.
' The victim is receiving support from specialist officers.
'A 54 year-old man who is not from Hampshire has been arrested on suspicion of rape and remains in custody at this time.'
HTB told Premer it would not comment on the case as it was a police matter.