The Foreign Office has said the number of British people feared dead in the terror attacks in the US is about 100, and could fall over the coming weeks.
Below is an unofficial list of British and Irish nationals unaccounted for on September 21, compiled by the Press Association.
Oliver Bennett, 32
Graham Berkeley, 37, an IT consultant whose parents live in Shrewsbury, was on board the United Airlines flight which plunged into the World Trade Centre's south tower.
Bella Bhukan, 23, from New Jersey, was working on the 104th floor of the north tower. Her family, is from Wellingborough, Northamptonshire.
Andrew Bailey, 29, from Birmingham, worked for insurance brokers Marsh and McLellan on the 93rd floor of the north tower.
Paul Bristow, 27, publisher for Risk Waters group, was at a seminar in the Windows on the World restaurant on the 106th floor of the World Trad Centre.
Geoffrey Campbell, 31, who had been due to take part in a conference hosted by publishing company Risk Waters Group, in the World Trade Centre.
Martin Coughlan, 53, from Co Tipperary, was working as a carpenter in the south tower.
Michael Cunningham, 39, broker for Eurobrokers in south tower. Originally from Ilford, Essex.
Patrick Currivan, 53, of Dublin, was on board one of the hijacked jets which smashed into the World Trade Centre.
Gavin Cushny, 48, of Isle of Lewis in Outer Hebrides. Working as computer consultant for Cantor Fitzgerald on 104th floor of the north tower.
Richard Dawson, of Southampton, was attending a convention in the World Trade Centre when the second plane struck.
Kevin Dennis, 43, a stockbroker, who lived in St John's Wood, north London, before he moved to New York to work for Cantor Fitzgerald. He had been on the 101st floor of the north tower.
Michelle Duberry has not been seen since attending the Risk Waters conference in the Windows on the World restaurant.
Robert Eaton, 37, a Cantor Fitzgerald broker, believed to have been working on the 105th floor of the north tower.
Michael Egan, 51, the Hull-born vice president of multinational insurance company AON, is believed to have died as he helped colleagues escape from the south tower.
Christine Egan, 55, a nurse working in Canada, was visiting her brother Michael's office while on a week-long holiday in New York.
Elisa Ferraina, 27, formerly from London, taking part in the Risk Waters Group, conference on the 106th floor.
Gerald Paul Fisher, 57, a senior executive in technology and strategy consultancy Booz-Allen & Hamilton, was meeting clients at the Pentagon.
Andrew and Timothy Gilbert, who are both in their thirties and originate from Ipswich, were working at the World Trade Centre.
Ron Gilligan, 43, from Merseyside, is thought to have been behind his 103rd-floor desk at Cantor Fitzgerald when the attack occured.
Ian Gray, 55, originally from Wick, Scotland, the vice-president, principal and treasurer of McBee Associates Inc. He was on the plane which crashed into the Pentagon.
Kieran Gorman, 35, a labourer from Co Sligo.
Catherine James, 37, a former concert pianist and originally of West Cross, Swansea, south Wales, was working on the 100th floor of one of the twin towers.
Nicholas John, a 33-year-old banker from Swansea, had been due to attend a meeting at the World Trade Centre and has not been heard from since.
Stephen Lawn, 29, from Broadstairs, Kent, who moved to New York three years ago to work as a money dealer on the 91st floor of the south tower.
Michael Lomax, 37, from Heaton Moor, Stockport, was working on the 93rd floor of the south tower when it was hit by one of the planes, the BBC reported.
Simon Maddison, 40, an employee with Cantor Fitzgerald. Originally from Harlow, Essex.
Eamon McEneaney, 46, originally from Castleblayney, Co Monaghan, who survived the 1993 bomb attack on the World Trade Centre. He was working as a financial consultant in the south tower of the World Trade Centre and has not been seen since September 11.
Charlie McCabe, 46, a father of four from Roslea, was working as a librarian in the World Trade Centre.
Ruth McCourt, 44, from Cork, and her four-year-old daughter, Juliana, were on the United Airlines Flight 175.
Ann Marie McHugh, 35, from Co Galway, and Sean Canavan, 39, are all also feared dead.
Damien Meehan, 33, a financial adviser whose family originally come from Co Donegal, was in the 88th floor of north tower when the first plane hit.
Stephen Morris, 31, whose parents live in Nantglyn, Denbigh, is missing. He worked for a finance company on the 90th floor of the World Trade Centre.
Christopher Newton-Carter, 52, from London, an associate director for banker Sandley O'Neill, was six floors from the top when the second plane plunged into his building.
David Rathkey, 47, from Maidenhead, Berks, was working on the 83rd floor of the north tower. The father of three was a systems consultant who was married to an American and had lived in the country for 20 years.
Rick Rescorla, 62, who was born in Hayle, Cornwall, vice president for security for Morgan Stanley Dean Witter, is missing after helping his colleagues flee the World Trade Centre's south tower.
Sarah Redheffer, 35, from Enfield, north London, was working for Risk Waters on the 106th floor of the north tower when the first jet struck.
Laura Rockefeller, 42
Karlie Rogers, a Sussex University graduate
Captain Timothy Stackpole, an Irish firefighter
Edward Saiya, 49, and his brother Art from Camberley, Surrey
Howard Selwyn, 47, from Leeds, was told to evacuate the south tower while on the phone to a colleague at his desk on the 84th floor.
Joyce Smith, 55, a Cantor Fitzgerald employee from Leicestershire was catering manager for the firm.
Derek Sword, 29, from Dundee, was working for American finance firm Keefe, Bruyette & Woods when the second jet went into the south tower.
Nigel Thompson, 30, from Sheffield, was working on the 105th floor of the twin towers for brokers Cantor Fitzgerald.
Simon Turner, 39, was among seven other British employees working at the technology conference in the World Trade Centre.
Jonathan Uman, 33, co-head of corporate development at Cantor Fitzgerald.
Melanie de Vere, 30, a publishing assistant with Risk Waters, grew up in Hayling Island, Hampshire before moving to London. She was at a conference on the WTC's 106th floor when it collapsed and her mother fears she is dead.
Jim Walsh, 37, a computer programmer for Cantor Fitzgerald from Nottingham.
Glen Webber, 35, from Wales, an e-commerce consultant.
Dinah Webster, 50, and Neil Cudmore, 38, who were attending a conference on the 109th floor of the south tower. They worked in the advertising department of a financial journal and were believed to have been planning to marry this year.
Vincent Wells, whose parents Charles and Julia are from Ilford, Essex.
Martin Wortley, 29, from Woolpit, Suffolk, was working as a dealer with Cantor Fitzgerald.
Neil Wright, 30, an options broker from Tilbury, Essex, was in the offices of Cantor Fitzgerald when the building was struck.