Not under normal circumstances, but December was a bad month. There were so many bags misconnected at LHR that BA was flying them to MXP to be processed (true story!); no statistics released on average delivery time for misconnected bags, but I've heard 14 days. Over 20,000 bags "lost" at one point, due to a failure of a baggage sorting system. BA recently held its annual meeting, and revealed that the 3 service disruptions last year cost over USD 200 million for BA (and the lost bags were maybe USD 50 million of that!). Under the circumstances I think Swanhunter's comments are well founded, and if anything understated in the classic British way.

Things are better now at LHR -- this week. Who knows when the next syste failure will occur? LHR was simply not intended to be processing the number of bags that it does now (the 1 bag carryon limit and liquids ban did a lot to increase the LHR baggage sorting problems, but LHR has had this problem for the past decade).