The BBC West region started on 1st September 1957 as part of the BBC Television Service, before becoming BBC One West.

BBC One West

The BBC South region started on 5th January 1961 as part of the BBC Television Service, before becoming BBC One South.

BBC One South

BBC One London

London

BBC One West Midlands

BBC One region covering Derbyshire, Leicestershire and Nottinghamshire.

BBC One East Midlands

The BBC East region started on 1st May 1959 as part of the BBC Television Service, before becoming BBC One East.

BBC One East

BBC One North West

The BBC North East & Cumbria region started in 1959 (tbc) as part of the BBC Television Service, before becoming BBC One North East & Cumbria.

BBC One North East & Cumbria

BBC One Yorkshire

BBC One Oxfordshire

Formerly part of a wider BBC One South East region that included London and part of the South region. Separated from BBC One London 2001-09-03 following reorganisation of the South East region.

BBC One South East

BBC One Cambridgeshire

BBC One Channel Islands

BBC One Yorks & Lincs

BBC One Scotland

Scotland

BBC Northern Ireland region started on 19th April 1955 as part of the BBC Television Service, before becoming BBC One Northern Ireland.

BBC One Northern Ireland

BBC One Wales

Wales

Sign language

The BBC South West region started on 20th April 1961 as part of the BBC Television Service, before becoming BBC One South West.

BBC One

BBC One South West

Horizon

Documentaries

Factual

Factual: Science & Nature

Factual: Science & Nature: Science & Technology

Horizon tells amazing science stories and reveals worlds you've never seen before.

Horizon tells amazing science stories, unravels mysteries and reveals worlds you've never seen before.

BBC HD

BBC Two England

England

BBC Two Scotland

Until 03/01/2009 BBC Two Wales (analogue) was known simply as BBC Two Wales. BBC Two Wales (digital) was BBC 2W. From 03/01/2009 BBC Two Wales schedules on both analogue and digital became identical

BBC Two Wales

Horizon: 2009-2010

Alan Davies

Marcus du Sautoy

Becky Parker

Seth Lloyd

Rob Liddell

Andrew Cohen

Horizon: 2009-2010: Episode 6: How Long is a Piece of String?

How Long is a Piece of String?

Episode 6

Episode 6: How Long is a Piece of String?

2009-2010

BBC Two - Horizon, 2009-2010, How Long is a Piece of String?

Alan Davies attempts to answer the proverbial question: how long is a piece of string?

Alan Davies tries to answer the proverbial question: how long is a piece of string? But the task soon turns into a mind-bending voyage of discovery where nothing is as it seems.

Alan Davies attempts to answer the proverbial question: how long is a piece of string? But what appears to be a simple task soon turns into a mind-bending voyage of discovery where nothing is as it seems.

An encounter with leading mathematician Marcus du Sautoy reveals that Alan's short length of string may in fact be infinitely long. When Alan attempts to measure his string at the atomic scale, events take an even stranger turn. Not only do objects appear in many places at once, but reality itself seems to be an illusion. 

Ultimately, Alan finds that measuring his piece of string could - in theory at least - create a black hole, bringing about the end of the world.

BBC Two

Knowledge, drama, comedy and the arts for a broad adult audience.

BBC Two is a lively channel of depth and substance, carrying a range of knowledge-building programming complemented by great drama, comedy and arts.

Factual: Pets & Animals

Series exploring topical scientific issues

Accessibility links

Programme Index

Horizon

2009-2010

Episode 6: How Long is a Piece of String?

Contributors

Genres

Formats

Brand

Series

BBC One South West

About BBC One