If you're looking for a day out that will both amuse the kids and get them interested in IT, or simply a trip down Memory Lane, the National Museum of Computing, based at Bletchley Park on the outskirts of Milton Keynes, could be just the thing. 

Not only does it have a working ICL 2900 mainframe, a bunch of PDP-11s and an air traffic control station that was in daily use at West Drayton just a few years ago, there's also a room containing all the personal computers you had as a kid - and they all still work and you can play with them...

Tony Sale with Colossus

Most famously though, the museum is home to a reconstruction of Colossus, the world's first programmable electronic digital computer. The original Colossus was built in 1944 to crack the Lorenz ciphers used by the German high command, but its existence was kept top secret for 30 years. 

Why was it kept secret for so long? Because it was known that the Allies had broken Enigma, yet long after the war some countries were still using Lorenz-type ciphers, described by computer historian and Colossus rebuilder Tony Sale (seen above) as "a million times stronger than Enigma", not realising that the Bletchley Park experts had cracked that too. 

That's why while the official line was that all ten of the Colossus machines built were dismantled on Churchill's orders in 1946, it wasn't true. A couple were spirited away to GCHQ - Tony Sale understands that one was still running in Cheltenham in the early 1960s - and it's also rumoured that one ended up in the possession of the US National Security Administration (NSA).

Help wanted

Now though, the museum needs help. It's trying to raise a £7 million endowment, which museum trustee Jon Fell says should be enough to keep it running into the future. Among the first corporate sponsors to sign up were IBM and PGP, but more are still needed. 

Fell stresses that the museum, which currently opens on three afternoons a week, wants to have as much as possible of its collection not just working, but usable by visitors.

"The aim is to produce an educational experience, to get people thinking how computing affects their lives - both the good things and the risks," he says.

"We hope this will be an inspiration for young people who come in to learn about computers, helping them get a perspective on the technology we have today," adds IBM's Andrew Hart. 

PGP's Phil Dunkelberger agrees: "Today we live in a disposable society that forgets its past, and as everyone knows, if you forget your past, you're destined to repeat it." 

He described the museum's campaign for funding as "the call of a debt that is owed by anyone in the IT industry. For example, we as PGP would not have a business today without the work done here at Bletchley - it was the on-ramp for many of the ideas we reply on today." 

Although entrance to the computing museum is covered by the £6 to £10 entry fee to Bletchley Park, where it occupies the WW2 buildings which originally housed Colossus no. 9, it's a separate organisation. 

(Indeed, Bletchley Park has its own funding appeals. In particular, it needs funds to preserve the famous wooden huts where the wartime codebreakers worked, but which were never designed to last this long, for all that they're now listed historic buildings.) 

It's separate too from the other two national computer museums, the Museum of Computing formerly based in space donated by Intel in Swindon, and the Centre for Computing History in Essex.

Does the UK need three computer museums? Perhaps not - and with the MoC currently in storage, and the CCH only open by appointment, consolidation could make a lot of sense. However, the three collections - plus a fourth display of computer exhibits at the Science Museum in London - all have subtly different aims, and of course different sponsors and backers, so I won't hold my breath waiting for it to happen. 

In the mean time, get yourself over to Bletchley Park and learn just how much today's IT owes to those wartime pioneers. Weekends look the best times to visit, as more of it is open then. If you can't visit in person, you can donate to both the campaigns online.