The Foreign Office said that as many as 40 British nationals were taking part in the aid flotilla attacked by Israelis as it headed to Gaza.
It is believed that the bulk of them are detained in a compound in the southern Israeli city of Be'er Sheva.
Here is a list of those believed to be involved - compiled from information supplied by relatives and campaign groups:
* Gehad Sukkur, 39, from Altrincham, Cheshire;
* Parveen Yaqub, 39, from Honley, West Yorkshire;
* Denis Healey, 55, originally from Portsmouth, Hampshire, now living in Cyprus;
* Kevin Ovenden, from Newham, east London;
* Nicola Enchmarch, from Wimbledon, south west London;
* Nader Daher, from Hendon, north London;
* Alexandra Lort-Phillips, 38, from Hackney, east London;
* Sarah Colbourne, from Hackney, east London;
* Ashan Shamrak, from north London;
* Hassan Ghani, from north London;
* Sidique Hajee, from Bradford, West Yorkshire;
* Peter Venner, from the Isle of Wight;
* Mohammed Bhaiyat, from Bradford, West Yorkshire;
* Nur Choudhary, from Tower Hamlets, east London;
* Baboo Zanghar, from Bolton, Lancashire;
* Tauqir Sharif, from Chingford, Essex;
* Cliff Hanley, from Bristol;
* Sakir Yildirim, from Bristol;
* Ismail Patel, from Oadby, Leicester.
Also believed to be among the passengers are Alex Harrison and Ibrahim Musaji. No addresses for them have been given.Reuse content