According to the the office of national statistics we had around 300,000 males 65 years of age in 2008. Even if half of them go for early retirement that leaves 150,000 extra workers in the system each year. Where do the extra 150,000 jobs come from?
Add women in their early 60s to that and you've got even more extra jobs to find when we already have an issue with unemployment.
Surely, unless we can magic up extra jobs from somewhere, we're just transferring that number of people from being supported by the government via the pension system to being supported via unemployment benefits?
In short it sounds to me like increasing unhappiness (as unemployment generally sounds more stressful to me than unwanted retirement) for the sake of a false economy.