One of the brown wires will bring power to this point, another will go to the switch, and the final brown wire continues on to the next light. The markered blue wire brings power back from the switch, when the switch is in the ON position.

You need to connect the brown that has constant power, to the brown that goes to the switch. Next connect the markered blue to the light, and to the brown wire that leads to the other lights on the circuit.

The green/yellow, and blue wires in your image are connected properly.

As you currently have it wired, you have the wire that feeds the other lights connected to constant power. So they will always be on.

Locating the hot

WARNING:

This procedure should only be carried out by persons with the proper tools and knowledge. And should be carried out with extreme caution.

1. Turn off the power to the circuit at the breaker/fuse box.
2. Disconnect all brown wires, and position them so that they are not, and will not come into contact with any other wire or metal object.
3. Turn the power back on at the breaker.
4. Using a multi-/voltage meter, touch one probe to the "neutral" wire block (where the blue neutral wires are connected).
5. Touch the other probe to each brown wire in turn.
6. If you get a voltage reading, mark that wire in some way.
7. Turn the power back off at the breaker/fuse box.

You should have gotten a voltage reading on only one of the brown wires.

WARNING:

If you got a voltage reading on more than one wire, STOP, do not follow the rest of these instructions. contact a local Electrician.

Now that you know which wire is the power wire, it's time to locate the switch wire.

Locating the switch wire

1. Find the blue wire that is marked as a switched hot wire.
2. Follow the wire back to where it exits the cable sheath.
3. Mark the brown wire that comes from the same cable sheath.

The brown wire that is part of the same cable as the marked wire is the switch wire.

Making the connections

1. Connect the brown hot wire to the brown switch wire.
2. Connect the blue markered wire to the remaining brown wire, and to the light.

Sounds like a simple case of a bad switch.

Note: a squirt of WD-40 into the right place in the sliding mechanism can help, or even fix the problem at least temporarily by lubricating the internal sliding electrical contacts. But getting the location right requires experience, and if you have to bring out an electrician anyway, they'll prefer to replace.

Do this with the power off by the way. And it's far better to take it apart and lubricate, compared to the squirt and hope method.

Consider upgrading to a dimmer model with a remote control, CFL compatibility, or other features.