Get a different timer. There are intermatic timers that use a switch rather than a semiconductor circuit. Sometimes they look identical to the incandescent-only ones. You have to read the ratings (they'll typically be good for fluorescent and small motors).

Much appreciated.

I agree. Sometimes there is something to be said
about the old fashioned mechanical contacts.

Just to clarify, is there a digital switch, intermatic, that does not have the semiconductor, or are you referring to a different type, eg. the one with the little dial?

I don't know which one you have, but Intermatic makes essentially the same electronic timer (with dusk to dawn or timed) available with either an incandescent only (semicondulctor) or more general (motorized switch). They look identical from the outside. I had the former and my CF fixtures flickered when off as well. All was well after I switched.

Here is a link that might be useful: Intermatic timers

It is normal, with a conventional bulb you just can't see it, but it's consuming current.

As others said, 'electronic' switches always have a little leaked current. A relay, or a mechanical switch is the only solution.

That being said, it probably won't hurt an LED.

"That being said, it probably won't hurt an LED. "

The LED is not the issue, the AC-DC power supply operating the LED can be damaged.

By the switchmode supply, as per another thread? I can see that. Whilst an incandescent bulb is in there, there's still current being drawn, except bulb is just acting like a resistor, not a bulb.

I guess I should have qualified it by saying OP must verify timer is compatible with LED and/or CFL.

The same topic seems to be coming up, over and over.

Or the CFL or LED must be compatible with an 'conventional' dimmer for it to operate from a typical solid state switch.