Most employments have removed retirement ages from new contracts, but the remaining ones are normally either too lazy to change old contracts, or because of the nature of the job requires early retirement. If the employer is using said age without good cause, then they may find themselves in front of employment tribunals. On the other hand, if the nature of the job requires it, then there are normally pension arrangements in place to cover this scenario.
transitional pensions for this scenario are often used to bridge the gap before state pensions kick in, but as they are on the way out, private pension planning might be a prudent approach to give the option of leaving work without having to be carried out. !!