This is what I think is crazy though. Joe Public wants to fly from A to B one-way. He checks the price for a o/w and finds it's £700. He checks the return price (cheaper fare bucket) and it's coming out at £450 (or £225 per leg), so he decideds to chance his arm and only use one-leg of the trip. BA not only get £250 less from Joe than they would have for his o/w (top fare bucket), but they also have a seat they cant sell (which would have made up for the £250 they lost on Joe's ticket) until the very last minute. Now, the fare bucket availability for each flight must be worked out on an individual flight basis each way, so why cant BA include o/w tickets in the normally discounted fare classes, but with an extra premium for o/w travel (which still works out less than Joe Public buying a return).

For example:

Fare class 1 (mega-cheap, no flexibility or change)
Cost per leg £225 (if part of a return) £337.50 if only a one-way (50% increase).
Fare class 2 (cheapo, but can pay for a changes to ticket)
Cost per leg £350 (if part of a return) £525.00 if only one-way (50% increase)

For each fare bucket, the number of seats available are used up regardless of whether they are a return or a single - the only thing that changes is the price, and once each bucket is used up, the prices go to the next bucket up (as they do currently with returns). Surely this would be a very easy thing for BA to implement???