Not as dangerous as it looks - these two are tethered to the chimney by a piece of blue string
Taken by David Mark from his office window in Balham, London. David said he would get back to us if they fell.
![Workers on house roof](https://d2vhdk00tg424t.cloudfront.net/MediaLibrary/s3/ubm-library/web/r/g/s/roof_relax.jpg)
![Dangerous workers on a roof](https://d2vhdk00tg424t.cloudfront.net/MediaLibrary/s3/ubm-library/web/l/b/e/roof_relax_1.jpg)
In case you didn't spot the blunders David pointed them out: "No tie off on the ladder, both operatives on the roof, thin rope around stack and each man's waist, and potential drop onto glass."