Thanks for the responses, all. I stand by my statement. As servants of the country, we all signed up to be used by the Government for purposes that they see fit. And that includes helping out in national emergencies.
Defending our borders, airspace, sea lanes and overseas interests are the missions that we can all focus on very easily (unless you're George Galloway). But we also signed up to dealing with domestic emergencies: floods, natural disasters, civil unrest and action that would interfere with the normal conduct of our essential services and the country's activities.
Firemen go on strike, the Government (who run the country and decide what the Forces do) are fully justified in sending in the troops to save lives. The tanker drivers threaten a strike that could immobilize the country, do the same.
If you are serving at a time when the Government needs you to keep the country functioning, just get on with it. There is a world of difference between this and using the Forces as cheap labour to park cars for the Olympics.
It's a legitimate role, not to be confused with political expediency.