This would be incredibly difficult, not only due to the fact that an average of 2:2 in your earlier years which count towards your degree, pushes up the percentage required to achieve a first overall, but also because a student who is getting 2:2s consistently is very unlikely to get firsts in their finals when the content is harder.
The people who have gone through this will be the ones who dossed about the first year or two but really got their act together for their final year. Not because of a lack of intelligence, just motivation. A person who is motivated and tries hard but still only achieves 2:2 grades is very unlikely to get a first later on.