Once complete, it will give academics or members of the public a single site that lets them search all the collections.
Once completed the search engine will index digitised books, newspapers, manuscripts, genealogical records, maps and images that date from 1500-1900.
"There are a number of electronic resources that have been created by universities and by commercial providers," said Professor Robert Shoemaker from the University of Sheffield which is heading the project. "They are all available, and all separate and some require subscriptions."
"What we are trying to do is join them up to create an integrated search facility so you do not have to conduct more searches than necessary," Professor Shoemaker told BBC News.
"We are creating a kind of sophisticated Google for those selected range of resources that we know are of high quality," he said.
Much of the work involved in the Connected Histories project will be tagging and annotating entries so classification systems are standardised.
"We want to provide a level of structured searching by names, places and dates," he said. "That information is provided on some databases and in some cases we'll have to identify it ourselves."
In general, said Professor Shoemaker, the different collections possess different types of materials so there is little overlap between them.
Currently 12 institutions have signed up to contribute their collections but more are expected to join in the future.
The initial partners include the University of Sheffield, the Institute of Historical Research, the University of Hertfordshire and King's College, London.
The first phase of the Connected History project should be completed by March 2011.
Once complete, said Professor Shoemaker, the search system will make it much easier for anyone, be they academics, amateur genealogists or curious citizens, to get at all relevant sources.
"Our hope is that this becomes perceived as the place to go when finding sources for British history," he said.
"I think in the fullness of time we should expect that everything will be on the web and we need a way to interrogate that material," he said. "It is designed to be infinitely expandable." Read more.