Here you can see a blocked gutter on a house we visited in Bromley. They were full almost to the brim with moss, debris and lots of stagnant water. If the client had left this any longer they would most likely have buckled under the weight and come away from the fascia boards.
We cleaned them out by hand, checked that the brackets were sound and that the seals hadn’t become looses or distorted, then washed them through
Before we left we checked that the water was flowing away down the drainpipes and that there were no leaks anywhere.