BBC's Genome Project offers radio and TV archive listings
The BBC has launched a test version of an online searchable catalogue of its TV and radio programme broadcasts.
The Genome Project is based on scans of Radio Times magazine listings published between 1923 and 2009. Searches bring up a synopsis, a cast list and an edit button.
It is designed to help the BBC identify programmes missing from its recorded archive and try to find copies of them.
A total of 4,423,654 programmes are included, from 4,469 issues.
The scheme was given its name because the corporation likens each of its programmes to "tiny pieces of BBC DNA" that will form a "data spine" once reassembled.
Most of the BBC's early output was not recorded, and later many shows were destroyed or wiped over.
The hope is that the project will lead to programmes being recovered if the public realises they have audio or video recordings of their own.
Specific shows can be searched for, alternatively visitors can browse the issue archive by year, providing a way to see old Radio Times covers.
The archivists said they expected searches for old Doctor Who episodes to prove particularly popular.
"Genome is the closest we currently have to a comprehensive broadcast history of the BBC," said Hilary Bishop, editor of archive development at the BBC.
"It is highly likely that somewhere out there, in lofts, sheds and basements across the world, many of these 'missing' programmes will have been recorded and kept by generations of TV and radio fans.
"So, we're hoping to use Genome as a way of bringing copies of those lost programmes back in to the BBC archives too."
The next step is to cross reference the Genome Project with the corporation's other records.
At this point, however, there are no details on the search results about whether a programme is missing.
Ultimately, the intention is that Genome will also provide photos, scripts and other materials held by the BBC.
For now, it allows the BBC's own staff to download a PDF of the relevant Radio Times magazine, however this facility is not currently available to others.
However, the archivists involved acknowledge that the project does not currently take account of changes to the scheduled broadcast - including coverage of the assassination, in 1963, of President John F Kennedy - and recognise other limitations with the current database.
"We know the data contains errors and we're asking for your help to find and fix them," said Andy Armstrong, an engineer involved in the project.
"We know, for example, that some programmes are currently showing up on the wrong days due to OCR [optical character recognition] errors on the dates.
"We also have work to do to make the site even more accessible to screen readers and other assistive technologies.
"And smartphone users may notice certain challenges with the current version of the site - it's better in landscape than in portrait. Sorry. It's on the list. We're working on it."
The team added it also planned to add regional shows not yet included.
The BBC has not said how much the project has cost, although a spokesman said that "any decisions were made with value for money for audiences at its core".