Police are investigating a serious assault which took place in Sark on Friday night.
It happened in the Bel Air pub around midnight.
The victim suffered what police have described as a 'significant knee injury', requiring an urgent medical evacuation to the PEH to be operated on.
Officers deployed to Sark on Sunday arrested a 20-year-old man who was transferred with the officers back to Guernsey.
Police say there were plenty of people in the pub throughout the evening, and they want to hear from anyone who has information.
If you can help, you're asked to call Guernsey Police on on 725111 or Crimestoppers on 0800 555 111.

Guernsey firefighters tackle round-island walk in full kit
No provider awarded subsidy for seasonal inter-island ferry service
Guernsey's key industry 'stable' in a turbulent world
Pubs can apply to stay open later to show World Cup games
Landowners reminded to clear Guernsey's streams of vegetation
Guernsey homelessness charity 'deeply concerned' at rising support need
Plans lodged to improve Guernsey's sea water Children's Pool
States record £45M surplus, but still warn of Guernsey's funding gap