You are the one who is talking about treasonous offences, Lord Haw Haw was convicted of and executed for treason for his activities at a time we were at war with Germany. So I'll ask again what has that got to do with Shamima Begum who has not been accused of treason but had her citizenship revoked under the 1981 British Nationality Act as a result of her association with terrorists.
To clarify I have no comment to make on the situation Shamima Begum is in, I'm purely trying to find out what the execution of someone convicted of treason at a time executions were commonplace has to do with a completely different set of laws today.
The execution isn't critical to the point I was trying to make. Simply that we saw fit to try and punish someone of treason even when they weren't actually a citizen of the country they betrayed. We didn't, as we possibly should have done, deny him access to the UK, try him alongside any other supporters of the Nazi regime.
There are however some similarities between the cases. We may not from our perspective have been at war with ISIL or Daesh or whatever we are terming them, but that is because we didn't recognise them as a legitimate state. But from their, and Begum's, perspective they were a state. And they were carrying out attacks against the UK and our allies in NATO.
It has been reported that she acted as a morality officer within the Islamic state. As such I think she should stand trial for those crimes. We may not like the fact that she is British, or that someone British acted in the way that she is reported of doing. But to my mind she is. And she should face British justice accordingly.
And the relationship and connections between the cases? Well there is, to my mind, a greater justification to try Begum as British than there was to Joyce. I know you think that the length of time between the cases negates the relevance, and I respect that opinion, however just how recent does an example have to be? These are, thankfully, exceptional cases.