The UKFI has outlined it strategy for the two banks it bought last year (well, 3 banks really if you include HBOS). The answer is sensible, but not pretty.
Due to the high prices paid relative to their current worth today, these banks are going to be in state hands for a long-time to come. It looks like it is expected to take them 5 years to earn enough to be re-privatised.
The talk of profit for the taxpayer is duplicitous too; I doubt the full calculations of the costs of increasing public debt so much are factored in. They may sell out of RBS at 70p a share one day when their average buy-in was 65p and claim a nice profit. But it won't reflect the cost of the public finances of administering the banks for so long, borrowing the gilts etc.
However, it is still a sensible move in that trying to get out of the stakes in the short-term would cause uncertainty in the markets. What is done is done and best to live with it. We don't need any more great ideas like telling the world we are going to sell all our gold and sinking the market in advance of the sale!