@Callum: Please read the comments on this bug and follow the instructions there. Telling us which bzr version you're using is also needed to diagnose what is happening in your case.
Also, from your comment, it's a bit unclear what your context is, you say: "my host does not support the plain HTTPS protocol." and "I receive this error when pushing to a bzr+https:// repository". Either you expect https to work or you don't.
What do you mean ?
Note that in almost all cases where we got this error message from pycurl, it was tracked down as a bug in pycurl or one of its dependencies, so please make sure you're using an up-to-date system and tell us which versions you're using.
Finally, as recommended in some earlier comment, what happens if you uninstall pycurl ? Recent versions of bzr's urllib implementation support https.
@Callum: Please read the comments on this bug and follow the instructions there. Telling us which bzr version you're using is also needed to diagnose what is happening in your case.
Also, from your comment, it's a bit unclear what your context is, you say: "my host does not support the plain HTTPS protocol." and "I receive this error when pushing to a bzr+https:// repository". Either you expect https to work or you don't.
What do you mean ?
Note that in almost all cases where we got this error message from pycurl, it was tracked down as a bug in pycurl or one of its dependencies, so please make sure you're using an up-to-date system and tell us which versions you're using.
Finally, as recommended in some earlier comment, what happens if you uninstall pycurl ? Recent versions of bzr's urllib implementation support https.