Did your grandfather fight at the Somme? Could you be descended from royalty or slaves? The huge popularity of the BBC series Who Do You Think You Are? shows just how main-stream family history has become, with thousands of people using their spare time to answer such questions.

Now much of a process that once depended on frequent trips to libraries and archives can be completed online, saving time and hundreds of pounds a year in rail fares or petrol, snacks and photocopying costs. Else Churchill, of the Society of Genealogists, says that the internet has “revolutionised” the hobby, although websites do not have all the answers.

Peter Christian, author of The Genealogist’s Internet, says that people starting from scratch – with basic details of grandparents or great-grandparents – should be able to take most lines back to the start of civil registration of births, marriages and deaths in 1837 from the comfort of home, ordering relevant certificates online and using online census data for 1841 to 1901.

Guides to the process can be found free on the website of the Society of Genealogists at www.sog.org.uk and at Genuki.org.uk . But access to most records comes at a price. Ms Churchill says that a subscription to at least one of the several commercial sites that give access to census and other data is almost always worthwhile.

Ancestry.co.uk is among the best-known of these and offers subscribers unlimited access to census data and other resources, including a range of military records and trade directories, for £6.66 a month or £79.95 a year. Ms Churchill says that popular alternatives include findmypast.com , which offers a basic package of records for £65 a year.

Indexes to births, marriages and deaths are available free at Ancestry and at freebmd.org , but certificates must be ordered from the General Register Office (GRO) at www.gro. gov.uk for £7 each.

There is no point in duplicating research. Several resources, including the subscription site GenesReunited. co.uk , can help you to track down other people – often distant cousins – working on the same family lines. Free mailing lists at www.rootsweb.com bring together people researching ancestors with a certain surname or who lived in a certain area.

Long-lost relatives may be able to pass on stories and copies of family documents and photographs. A number of online resources do the same job. One is oldbaileyonline.com , which has free accounts of more than 100,000 trials at the London Central Criminal Court from 1674 to 1834. A quick search finds the trial in 1816 of Daniel Garcia, pickpocket and brother of one of my ancestors. His defence – “I am as innocent as the child unborn” – did not wash and he was transported to Tasmania.

Other interesting snippets may be found in ancestors’ wills. Thousands are available at the Documents Online section of www.nationalarchives. gov.uk for £3.50 each.

CASE STUDY: Archive access from home

Jeanne Bunting, 72, has been tracing her family history for 20 years and has uncovered links to the actress Joan Simms and to King Edward VIII’s chauffeur. She uses Ancestry and Findmypast almost every day and says that the internet has enabled her to cut the number of visits from her home in Ash Vale, Surrey, to libraries and archives in the capital.

“The cost of four or five visits to London pays for a year’s subscription to one of the websites,” she says.

Mrs Bunting advises beginners to use free mailing lists and forums where, she says, “experts in all fields willingly give of their knowledge”.