Properly blacking out windows/blinds

We got blackout blinds fitted by a cheap warehouse place (fitted over the flush edge of the inside frame) and there’s light coming in around the sides and top…what’s the best thing to create a proper blackout effect?

I’ve seen roller shutter type blinds in germany where the blinds were fitted into a sliding recesss that was fully sealed. Just wondering if there’s anything a bit cheaper, short of taping foil over the windows!

Make a baffle out of something for the blind to slide up and down in?

Some of that right angle shaped wooden moulding, fastened to the wall…
A peice of timber, with a slot routered out for the fabric to run up & down, fastened to the wall…
Magnets, or velcro, to hold it against the frame…

Did a simmillar thing in our old caravan.

these:
night night
They work perfectly in our wee one’s room – velcro sticks on to the window frame, then the blackout fabric just sticks to that.

Brick the offending window up – very effective…

Thanks for the ideas. I’ve bought some blackout fabric and some velcro and I’m going to try and DIY! £8 for enough to do a room, if it works then great.

We used some uPVC 90deg edging – worked a treat.

You’re wasting your time. It won’t help when the bomb is dropped.

Sorry, wrong decade.