Hi, can you tell the date of my Alan bicycle? I cannot find it engraved on the frame. I post a picture of the bottom bracket with dimensions in cm and the serial number, but nothing else. The decal on the seat tube lists the championship victories and says that the last victory was in 1976. So, my frame is not earlier than 1976, but which year exactly?

It has attached rear brake cable tunnels which were reportedly introduced for the 1978 model year. Also, in 1979 they added an open format date code to the top, drive side of the seat tube. It should tell you the exact manufacturing date. If it's not there, then it should be a 1978 by virtue of the cable tunnels. Here's a link to fairly exhaustive ALAN dating guide; https://www.dcisite.be/en/artikel-info/alan-guide

The cable guides on my bike were introduced in 1978. The numbering on the seat tube was introduced in 1979. Since I don't have numbering, it follows that my bike was produced in 1978. Thank you T-mar!

Do I also have the "lethal" fork that was supposedly prone to failure? Mine has a round section, for sure, otherwise I don't know what to look for.

you may be conflating the "Death Fork" found on many Viscount/Lambert with the ALAN, which is also made of alloy but AFAIK did not have a particular record of catastrophic failure.
YMMV
The "common knowledge" weak point ascribed to many ALAN frames is cracking of the headlugs, always good to make periodic checks of them, may as well extend your check to all other lugs, joints and tubes.

I agree with unworthy1 about the fork.
The first model, the Competition, had a fork with a steel inner tube, the second, yours, had a fork with a alloy inner tube. Maybe here began a story ... ?

Go to the Alan web site and take a few pictures and ask. They're very responsive.

I had an '84-'85 Alan with an alloy steerer. I was told it was a "death fork". I rode that thing hard for 55,000 miles. I still have all my teeth. At about 53,000, I noticed the seat lug was cracking on the bottom back. It was running up towards the slit. I rode it until I hit the 55K and then retired the frame.