This fault may be due to salted UK roads but is worth checking.
ST1300 Urgent News
Following a near-catastrophic accident, a number of Pan-Clan members report a serious problem with their ST1300's. It relates to the centre clamp underneath the bike where the exhausts meet.
For one member, this was so rotted that it collapsed as he was riding, the rear tyre then hit the clamp as it fell causing a blow-out. Others have checked theirs and found that the clamp has come away in their hands. see picture.
Replacement clamps are relatively cheap, and a lot better than the possible alternative.
Update:
Having just had my ST1300 MoT'd, I got a report that the clamps on the silencers were splitting (not the central one that gave the problem above). Having checked all three clamps I have now obtained a set of the 3 clamps required (2 large, one smaller), in stainless steel, from ebay. Cost, including the £1 premium for 1st class delivery (=next day for me) was £17! I was quoted almost £120 by the garage doing the MoT to just replace the 2!!