http://www.bbc.co.uk/news/uk-24092931

It does read like a bit of a scam on the government's part.

It is not that difficult, but they would need to be a lot fitter than you or I at that age. Though I would have thought that many could be given alternate posts at that age, but how many such posts would there be?

You've got 'management' posts, and they could be doing the bits that don't actually involve carrying people out of burning buildings like going around schools and doing building fire safety checks and etc. Contrary to what they might want to you believe, the majority of firefighters don't actually spend that much of their time fighting dangerous fires.

However, nevertheless, I wouldn't want to be the poor bugger who did get the 59-year old trying to rescue me because they're a bit shorthanded just then.

Yes but there will not necessarily be that many management posts. 1 maybe two per fire station. A few more at HQ, though retraining firefighters to do the office jobs might be one long term solution. As you say fire prevention and safety inspections are a big part of the jobs. These could be done by older officers. There are also needs for post fire inspections to detect arson and safety violations, these could be done by older firemen and women. Though providing firemen with gyms to maintain fitness might solve the problem as they get older.