Isn't there an obligation for accuracy
See title. By discarding the Windrush data and then maintaining a record of an individual's immigration status which is then, as a consequence of having discarded that data, inaccurate don't we then have a case where the home office holding inaccurate data as a result of their own negligence. Isn't it reasonable to suggest that by discarding the data they have in some way forgone their right to hold other subsequent data on the data subject. I suspect that this question would be extremely unclear in law and would have to depend on action for maladministration rather than just data protection.
For example, this would be similar to me destroying all records of a customer's contract and then when they contacted me for contract fulfilment claiming there was no contract. This would typically end up being treated as fraud with the only defence against criminal liability being a claim of incompetence. The Windrush data was destroyed after the beginnings of a period where the home office had started it's policies that made this data important.