[6bone] Dualing IPv6 announcements

[Hank Nussbacher]

BT and JPNIC/WIDE are both announcing these prefixes:

mcast#sho bgp ipv6 inc
BGP table version is 479, local router ID is 192.114.99.52
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

    Network          Next Hop            Metric LocPrf Weight Path
*  2001:200::/35    3FFE:2000:0:41D::22F
                                                            0 559 6830 1752 ?
*>                  2001:798:2020:10DD::1
                                                            0 20965 11537 
2500 i
*  2001:200::/32    3FFE:2000:0:41D::22F
                                                            0 559 6830 1752 ?
*>                  2001:798:2020:10DD::1
                                                            0 20965 11537 
2500 i

It looks like WIDE does "own" this:
inet6num:     2001:200::/32
netname:      WIDE-JP-19990813
descr:        WIDE project
country:      JP
remarks:      upgraded from /35
admin-c:      JM46-AP
tech-c:       AK27-AP
tech-c:       KN9-AP
status:       ALLOCATED PORTABLE
notify:       kato@wide.ad.jp
notify:       kenken@sfc.wide.ad.jp
mnt-by:       APNIC-HM
mnt-lower:    MAINT-JP-WIDE
changed:      hm-changed@apnic.net 20030423
source:       APNIC
so the question is why is BT announcing this and how come prefix filters 
aren't stopping this?

-Hank