Lawyer Ben Emmerson QC advises the UN on how to protect human rights during the fight against global terrorism.

He told HARDtalk's Stephen Sackur that while recent revelations from the US whistle-blower Edward Snowden may have been surprising, we should never have imagined that our emails were secure, comparing unencrypted communications to "putting a note on a notice board".

You can watch the full interview on BBC World News on Thursday 9 January at 16:30 and 21:30 GMT, Friday at 04:30 and 09:30 GMT and Saturday at 07:30 GMT. It can also be seen on the BBC News Channel at 00:30 and 04:30 GMT on Friday 10 January and at 00:30 GMT on Saturday.

Watch more clips at HARDtalk's website