shell prompt undesired characters

[Dan Davison <davison@stats.ox.ac.uk>]

I am having trouble getting a clean prompt with bash running under M-x
shell. Each line in the shell starts with

^[]0;~\a

(
I don't know how those two control characters will appear to you; what I
see in my emacs buffer is
^[]0;~^G
)

This is true if I set PS1='', so I believe my problem is not related to
escape characters in $PS1 (in fact they work fine if I use them).

I have tried with the system default .bashrc and the problem
persists. However, if I change to sh, then I get a normal, clean prompt
that displays just the contents of PS1.

Where are the strange initial characters above coming from when I run a
bash shell in emacs and how can I fix it?

Thanks a lot,

Dan
emacs 23.0.60.1
ubuntu 8.10