Constant solid red light on smoke alarm - please help!

[electricityclueless]

Looking for advice please; I'm completely clueless about whether a solid red light on a smoke alarm indicates something immediately dangerous - I do however know that red lights aren't usually a good sign!

The alarm was chirping earlier, whilst the continuous red light was showing. I tried vacuuming through the vent in accordance with the instructions. This made no difference. I then changed the battery ( it's a mains smoke alarm with battery). This has stopped the chirping, but the continuous red light remains.

Please could anyone advise whether this is immediately dangerous? Do I need to get an out of hours electrician tonight, or can it wait until tomorrow? Is there anything else I could try to fix it myself? Thanks very much.

No help but bump.
Is it also a carbon monoxide alarm?

Thank you - no, it's only a smoke alarm

if it's a mains-linked alarm it might have reached its end of life and need replacing

however

if the mains supply has failed, due to cable damage or a breaker tripping, it will cry until you attend to it (and will run the battery down)

it is common practice to supply mains alarms from the lighting circuit so that householders will notice if it trips, and will be motivated to fix it.

It will not be dangerous unless your house catches fire before it gets fixed.

p.s.

so check your consumer unit for any tripped breakers.

Thanks so much PigletJohn, very relieved that it's not immediately dangerous. Electrician coming later this morning. Thanks again!