We've been using Dettol Mould and Mildew remover for several years now, and it is highly effective and works very quickly.
For example; we find that the slime-moulds tend to build up in the nooks and crannies in the shower cubicle in spite of regular cleaning and an efficient extractor fan. But only a few minutes after the application of the spray they are all gone, and then taking a shower and rinsing down the surfaces leaves it all clean for at least another month or so.
Another example; during one winter some of the plaster low down on a white wall showed several black marks that would not wash off, but five minutes after a spray with this they were gone, and have not returned in subsequent years.
The product label indicates that it contains; <5% anionic surfactants, disinfectant (sodium hypochlorite 2.59% w/w), perfume. In other words, it is some washing-up liquid and bleach in a handy squirty spray pack. The spray nozzle has two positions; ON - spray, and OFF - locked shut.
The spray mechanism does not leak or dribble on to your hand, unlike many other sprayers. It is sufficiently good that we have refilled empty containers with suitable contents and re-used them for other spray functions; damping the ironing, misting plants, wetting wall-paper, potential fire-extinguisher (when doing some soldering on plumbing), eliminating greenfly/blackfly, etc.
It is widely available from more competitive suppliers.
Addendum 4th November 2012
I've noticed on our most recent DMM remover bought from WR that it is almost impossible to remove the sprayer-top from the empty bottle without destroying it. This improves the safety of the system while it still contains the bleach, but it also means we can no longer re-use the empty as a handy spray bottle for something else.