Obstacle Lighting in the UK
 

In my wonderful new SkyDemon program all the NOTAMS are shown on a map (much better than the AIS web site).

I note that many tall masts have notams posted with "OBSTACLE LIGHTING U/S". A casual count shows at least 9 of these including some of the tallest masts in the country.

Is this just a penny pinching excercise?

Bill

Ask the people who own/operate the mast... Other questions to think about are whether the mast requires an obs light, and how long it's been u/s. If it should be lit and it's been u/s for more than a reasonable time, speak to the CAA and ask them why.