Absolutely !
Yes, you will need a passport at each end of the journey.
No; just the passport will suffice.
no all you need is just your country passport
There is no minimum validity requirement. Portugal is in the EU. All EU citizens (including UK) can travel to Portugal up to the last day on their passport. Different rules apply to citizens of non-EU countries.
You need a passport or an ID.
Yes, you will need to show your passport.
Yes, You always need a passport (or EU national identity card) to get in our out of the UK.
No you need a passport.
Is a swaziland passport need a visa to uk?
Yes you need a passport whenever you leave the United Kingdom because you need it to get back again.
Yes.
Strictly speaking, as the UK and France are both in the EU, you don't need a passport to travel to France. However, you will need a passport on your return to the UK. To be absolutely certain, you should check with the French Embassy.