I don't think any cultural service can consider itself immune from cuts and they are a bit of a soft option being nice to have rather than being essential. I love the Horniman but I love essential services more and would prefer to sacrifice the former to the latter. I don't think we have seen anything yet re the cuts in public facilities and services.
I do hope that the Horniman won't be proceeding with its rather expensive expansion plans in the current climate? That would hardly be prudent.

I was thinking today of some of the museums I visited in the past in Eastern Europe where the curators opened up each room for guided tours one at a time and turned the lights on and off and in any case were only open one or two days a week to save money. It may sound like a joke but I suspect that this might turn out to be reality in these times of austerity. Some of us remember the time when TV went off at 10pm in order to save power so perhaps its not that far fetched.

There was a time when museums in this country were charging for the entrance, and even then Horniman museum was free. From what I heard at the time, the management of the museum could never charge an entrance fee, as this was a condition of the Horniman’s Trust which no one could get around even then. The trustees may face difficult time in running the museum if its funding gets cut, but 2015 is a bit far away in these challenging times and one would hope they would not immediately be looking at the closure.
As already mentioned cuts in social services are more imminent danger.

The current expansion plans (new education centre, improved animal enclosure, and landscaping) are mainly funded by the National Lottery, not directly from DCMS. This money is still safe and work has already begun in some areas of the gardens.

Two threads re museum funding merged.

Granted about the Lottery funding but I think such funding in the future will have to be used to provide basic amenity rather than expansion plans. Better to be slightly behind the times and open, than fantastic and shut.

However there are alternatives such as the donor and patronage model used in the US but that usually comes with terms and they might not be acceptable to the Horniman Trust.

From the News Shopper:

The land where the museum is and the nature trail is very precious and I hope this is not a trick to reduce that land to rubble, so they can build up new homes there. The views from the museum and the surrounding areas are the best in London and you can immagine how many developers would like to put their hands on.
We should start a petition to save the museum before the current funds are out.
Anyway, why these decisions are taken without consulting us?

Given the statements from the museum and the DCMS I think such a petition to 'save the horniman' is unnecessary and would only be accused of scaremongering.

The Horniman Gardens are protected as a site of nature conservation importance, green corridor, metropolitan open land, green chain walk, and part of a conservation area. This would make it very difficult for any developer to build housing on the site.