Illegal immigrant caught for driving with license

Welcome Mary2329

First of all, it doesn't matter whether the driver was or not an EU license holder. (The UK is no longer in the EU not that matters)

Furthermore, are you really are asking this on a public forum?

My guess is BOTH your friends will be detained and then deported if one any if not a British citizen.  Also will be blacklisted into entering the UK.

Your Lawyer will tell you all this...........

Many thanks for your input Sam. Your advice is much appreciated and I'll pass it to the enquirer  however I would clarify a few things in your comment. It wouldn't be my lawyer, it would be ‘his' lawyer who had been in this situation.
I'm a British citizen myself born and raised here and never been in such a situation hence wasn't able to answer the query of the person asked me this question. I don't think there's a problem asking this question on this forum where people exchange information to enlighten each other's knowledge for wider community- privileged or under privileged, vulnerable, homeless etc. I'm not responsible (no one is; like yourself) for actions of friends and family and anybody on this forum and in this world however if someone asks a question I can either answer based on best of my knowledge or get further information through other people's experience and knowledge via forums such as this one.

Being judgmental is the downfall of humanity, I'm afraid!

Many thanks Sam

To begin with the fact that your friend is illegal then he should not drive a vehicle in this country.
If he was legal then he would have been allowed to drive with his non British or Eu licence for 12 months afterwards obtain a British drivers licence.

Already by being illegal that means he is committing a crime and as such should be reported to immigration. 
If he wants to seek asylum then the same applies he should approach immigration with his solicitor.
You can find your answers on driving in uk on Direct Govhttps://www.gov.uk/driving-nongb-licence/y

Did your friend have a foreign driving licence from anywhere at all? If so then as I understand it this would entitle him to drive in this country for up to12 months before he is obliged to obtain a UK licence. So if he had a foreign licence it will depend how long he has been in this country whether that will cover him.
As regards the insurance, did the car's owner have a comprehensive policy? If so, those can sometimes extend to cover anyone else driving with the policyholder's permission. It may be worth checking that out.
However even if your friend cannot make use of these legal defences and has to plead guilty in the end, I cannot imagine that relatively minor offences of this nature would result in his being deported, unless there are other reasons for doing so - e.g. if he is an illegal immigrant, or is wanted by police for more serious offences.