Anyone tracing their family tree will, at some point or other, have to dip into the National Archive. There are two main sites in London: the Family Records Centre in Clerkenwell covers the Census returns (1841-1901) and indexes of Births, Marriages and Deaths, as well as some other documents, such as Wills and Probate records.

For everything else, you will have to come to the main site in Kew. Housed in an enormous modern building, set amongst attractive gardens and small ponds, it's a very pleasant venue (and, for modern architecture, not half bad).

The contents are formidable, and include:

- Papers from the Central Courts of Law from the 12th century onwards
- Medieval records of central and local government
- An impressive collection of maps and plans
- Records of wills, naturalisation certificates and criminal records
- Service and operational records of the Armed Forces
- Foreign and Colonial Office correspondence and files
- Cabinet papers and Home Office records
- Statistics of the Board of Trade
- Other historic documents relating to a wide range of industry (mostly those which were nationalised at some point).

Using the facility is a little intimidating: you are strongly advised to look at their web-site first. (The motto here is to plan ahead, in all respects.) You have to have a National Archives Readers Ticket made up on your first visit, so you will need to bring with you various forms of ID. This is to protect access to what is an incredibly valuable collection of materials.

Once inside, you can only take paper and pencils in with you, in clear plastic wallets. To facilitate this, there's a large cloakroom with lockers for clothes and bags, as well as a small cafe, restaurant and shop, just through the main foyer. You have to sign in and out each time you enter the main records area. The staff here can be a little officious, but the Archive staff are generally very helpful indeed.

There are plenty of staff at the help-desks to get you started, although - as with all such searches - it pays to do as much homework as you can online and from more accessible documents first. (There is a free and comprehensive, although rather complicated, search tool for their entire archive on-line - accessed through their web-site).

If you want to see original documents, you may have to wait for up to 40 minutes, so it is worth getting going quickly and ordering the first documents as soon as you can, aiming to keep up a steady flow of requests (assuming you want to order that many!) through the day.

An alternative is to order documents in advance, by e-mail or post (not by phone) but for this you'll need the document reference, and a valid National Archives Readers Ticket. (CARN tickets from the County Archives Research Network are NOT valid). Ordering in advance is also essential for any records held off-site.

Indeed, waiting is part of the process here, so bring something with you to read, if you are liable (like me) to want to see the originals of records. You will also have to wait to photocopy them, as fragile documents need special handling. It pays to be patient, and leave plenty of time - plan on spending at least half a day here for any specific search.

Most people are looking for military records, and these are arranged in a separate room, and are generally easier and quicker to access. I was looking for some of these, but also the employment records of several Great and Great-Great Grandfathers who worked on the railways in the 19th and early 20th centuries. It was amazing - and a privelege - to handle such documents, and see their signatures.

Getting there if fairly easy: there are several local bus routes passing by the front entrance, although most arrive by train or underground to Kew Gardens Station, from which it is a ten minute walk (leave the station in the opposite direction than for Kew Gardens). The site has 116 parking spaces for cars, (not bookable, so first come, first served) as well as provision for motorbikes and for disabled visitors. Parking in the surrounding streets is limited. Disabled access within the building is generally very good, and if you need special help, they have a named contact to get in touch with, to help plan your visit (details on the web-site).

NB: Building work is currently underway, due for completion in late Spring 2008. This will reduce seating capacity, as well as lengthening document retrieval times.