If you are considering making the senior person in a team redundant, to avoid a finding of unfair dismissal, read on.
In a redundancy situation, amongst other things, you must have a proper redundancy situation, and follow the correct procedures, including consultation. You will also need to consider the pool for selection . In other words, whether any of the rest of the team have sufficiently similar jobs so that you need to consider them for redundancy instead. You should discuss your chosen pool, or lack of one, as part of the consultation.
Bumping is where a more junior team member is made redundant, so that the more senior person (who is really redundant) can take a demotion instead.
Thanks to a recent appeal court decision (which can be found here) in appropriate cases you should now discuss bumping as well, as part of the consultation. There used to be a view that this only needed to be taken into consideration, as opposed to discussed with the employee.