I will reply separately to Steven Broom's comment (quoted in the post above) that he enjoys finding artefacts and cannot see the harm as long as he acts responsibly.
"Historical finds [...] can be the trigger that fires up a society's interest in the past."
Absolutely true! Actually handling an ancient object - rather than merely viewing it in a museum case or in an illustration - sends a chill down my spine. It is a thrilling experience that makes the past seem almost tangible.
The thrill of actually finding the artefact yourself is even more exciting - and I don't think anyone in their right mind could object to you coming across the odd Roman coin or Anglo-Saxon brooch. But the keywords here are "acting responsibly".
You have commendably stressed that you act responsibly in recording and reporting your finds. But that facet of acting responsibly was only part of what I was getting at in my criticism of the attitude of many metal detectorists. Personally, I am convinced that one of the most vital facets of acting responsibly in any pursuit that may threaten a fragile resource (whether it's bird eggs, wildlife or ancient artefacts) can be summed up in a single word: moderation.
I understand there are literally thousands of metal detectorists armed with extremely sophisticated machines, many of whom go searching for ancient artefacts every chance they get and often even on large rallies - typically in the misguided notion that they are "saving history". They have their own magazines, clubs, blogs and forums, and are frequently featured in the news (which encourages thousands more to join them). That is not my idea of moderation.
I genuinely applaud your own ethical attitude, Steven, but it is the scale of metal detecting that I find worrying and many are nowhere near as ethical as you. Even if every item really was recorded and reported, the prospect of thousands of untrained amateurs sprawled over England and Wales selectively digging up thousands of ancient metal artefacts as fast as they can grab them is more than a little disconcerting to those of us who value the evidence of history. And no, ploughsoil is not a carte blanche.
I understand the thrill of finding things but let's scale it down a bit, can we?