calibre crashed with SIGSEGV in PyObject_Call()

Had just shut Calibre down after importing a new book and downloading metadata for it. Shutdown seemed normal until the crash message. I was not running Calibre through the command line so can offer no more information. Calibre had not been working (reported crash on startup) until a couple of days ago when Calibre was included in the Ubuntu 13.10 updates.

ProblemType: Crash
DistroRelease: Ubuntu 13.10
Package: calibre 1.0.0+dfsg-1
ProcVersionSignature: Ubuntu 3.11.0-4.9-generic 3.11.0-rc7
Uname: Linux 3.11.0-4-generic i686
ApportVersion: 2.12.1-0ubuntu3
Architecture: i386
CrashCounter: 1
Date: Thu Sep 5 09:18:14 2013
ExecutablePath: /usr/bin/calibre
InstallationDate: Installed on 2013-05-13 (114 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Alpha i386 (20130511)
InterpreterPath: /usr/bin/python2.7
MarkForUpload: True
PackageArchitecture: all
ProcCmdline: /usr/bin/python2.7 /usr/bin/calibre
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x8118bb3 <PyObject_Call+19>: mov 0x4(%esi),%eax
 PC (0x08118bb3) ok
 source "0x4(%esi)" (0x00000004) not located in a known VMA region (needed readable region)!
 destination "%eax" ok
 Stack memory exhausted (SP below stack segment)
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: calibre
StacktraceTop:
 PyObject_Call ()
 ?? () from /usr/lib/python2.7/dist-packages/lxml/etree.so
 ?? () from /usr/lib/python2.7/dist-packages/lxml/etree.so
 PyEval_EvalFrameEx ()
 PyEval_EvalCodeEx ()
Title: calibre crashed with SIGSEGV in PyObject_Call()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm autopilot cdrom dip lp lpadmin plugdev sambashare sudo