Thanks to a double century by Jonathan Trott and centuries by Alastair Cook and Ian Bell, England amassed 496/5. After adding just 5 runs to their overnight score, England declared to give themselves a herculean task of bowling Sri Lanka out cheaply. The reason to bat on Day 5 was obvious, Ian Bell needed two runs for his century. But, it not only meant England batted for 2 overs, it also meant a loss of 2 overs. In the end, England managed to win by an innings and 14 runs but if Sri Lanka would have managed to keep 1 or 2 wickets in tact, questions would be raised about whether a century is more important or a victory. And we all know what the priority should be. So, yeah I don't agree with their decision.
Though they don't deserve much flak after their unbelievable victory. Before the Test, I did expect England to win, despite the ground being Sophia Gardens, where England and Australia stocked up 1361 runs for the loss of 25 wickets together in the Ashes '09. Sri Lanka escaping a Test defeat in England just doesn't make sense. But only 298.2 overs were bowled in this Test (450 overs are bowled if a result is not achieved). A result was achieved here, but the rain delayed start of play on almost all days. Here is a quick recap:
Day 1 - Four and a half hours
Day 3 - Three and a half hours
Day 4 - Four hours
Day 5 - Four and a half hours
Here is what Blake from Australia sent Cricinfo before the start of Day 4:
How can England become #1 in the world when they don't believe they can clean up a team in one day?" asks Ryan. "Remember what Australia did to them at Adelaide in the 06/07 Ashes?
Since there is not enough time for england to amass enough runs and then bowl out sri lanka for a chaseable target, England may as well bat the next 2 days, give a chance for Cook and trott to knock up 200-300 each.