I have seen magpies raiding the nests of sparrows in our ivy-covered fence and I have in vain tried to fight them off, but most of the damage happened in the early hours of the morning. We live in a suburban garden area close to the Thames where sparrows were thriving and even nesting under the eaves of our house until about three years ago, when they suddenly disappeared together with a sudden rise in the number of magpies and jays.
Nobody around here has used pesticides and insects are plentiful. Song thrushes and blackbirds have also declined and I have seen their nests being attacked by magpies.
It's about time magpies were taken off the protected species list. I sorely miss the garrulous chirpiness of our former common garden friend, the sparrow.