Here's the joke, sent by an equally grey-haired neighbour:

To save the economy, David Cameron will announce shortly that he is ordering the Home Office to start deporting old people (instead of illegal immigrants) in order to lower the Pension and Benefits Bill and NHS Costs.

Why? Well it makes sense:

Old people are easier to catch, and will not remember how to get back home!

I started crying when I thought of you.

RUN OLD FRIEND RUN!!!

Well... someone sent it to me and I'm not going alone!