The government cannot make long-term plans to spend the income received from arbitrary donations like this. Charities handle it by encouraging people to make r

The government cannot make long-term plans to spend the income received from arbitrary donations like this. Charities handle it by encouraging people to make regular donations and by conducting campaigns to raise money for specific purposes. Extra money received by the tax office might help to pay down some existing debt or some other one-off expenditure, but it cannot be used to make ongoing improvements to public services. However, I would not be surprised if they have to keep extra money aside, possibly for years, in case of a claim for a refund (or at least keep a budget line for it, which amounts to the same thing).