score:9
Trying to do this as conventional rental (Hertz, Avis, Europcar, etc.) will be extremely expensive, even if you find one. It's also inconvenient to drive a car from the "wrong" side, so I would at least break it up between the UK and the rest of Europe.
Unless you are planning to drive every single day, you may be better off with a combination of flights, trains, ride share, local public transit, and short term rentals. In most larger cities, having a car is actually a headache since traffic tends to be bad and parking is sparse and expensive.
Short term rentals can be conventional and "car sharing": For example in Germany there are services like https://www.car2go.com/DE/en/ (not intended as endors*m*nt), where you can simply pick up a car nearby and drop it at your destination (in the same town).
Trains and flights are good for larger distance (my wife and daughter just flew from Berlin to Rome for $17,- each). Once in you are a larger city you can rent a car to drive around locally and explore the surroundings. Local rentals also ensure that you have the right equipment and configuration at a reasonable price.
Upvote:1
There used to be a car hire programme called Le Swap. Suppose you are heading from the UK to France, you would return your right hand drive UK car, travel by Eurostar, and collect a left hand drive car on the other side. I cannot easily find evidence that this programme still exists but you could still try to arrange something similar. Look for rental locations at the points where you cross water. The side of the steering wheel issue won't apply between the UK mainland and the island of Ireland but the cost and complications of taking a rental car on the ferry would still apply. This strategy would certainly work if you were flying over the water but will probably work by ferry or train as well.
If you really want to drive all the way then it might actually be cheaper to buy a car. Still expensive and complicated but maybe a little less less so. There have been some recent questions on this subject.
Upvote:1
There are some regulations that ban EU citizens driving non-EU rental cars in the EU.
https://www.theguardian.com/money/2016/may/28/eu-citizens-car-hire-switzerland
This can be awkward for hiring in Switzerland and presumably the UK shortly. You may also find insurance more expensive as a result.
Upvote:2
Typically, there is little trouble in taking a rental car through all the countries you listed - I have done more than half of them in the same rental car already. It becomes only difficult if you would want to go further east, like Bulgaria or Poland, as most car rental companies don't allow that.
Your main issue will be cost for the one-way (an arm and a leg, for sure), and to find a company that accepts international one-ways. Consider that the company has to get the car back to the original country, so they have to pay someone to fly to your destination, and drive the car all the way back.
It's worth a try, but you would save thousands by making it a complete loop - for example, fly to France, rent, drive directly to GB, and then start your trip. At the end, add a day, and drive it back to France. You will lose a day each at the beginning and at the end, but save serious money.
Note also that rental are typically not allowed over 30 days. You will have to turn the car in and take a replacement every 30 days latest.
Upvote:3
The solution here could not be simpler,
Just hire a car in the UK (pick it up and drop it off anywhere you want), and
Just hire a car in Europe (pick it up and drop it off anywhere you want).
(It's trivial to transfer between say Folkestone and Calais by train, or between any UK airport and say Lyon.)
It's completely commonplace to do this.
You'd be one of a zillion tourists doing it this year!
The idea of using one car for both UK/Europe is a non-starter, just forget about that.
One of the great joys in life is motoring around the Continent. Enjoy!
Some further points:
https://travel.stackexchange.com/a/38154/19233
One-way car rental in Europe is fantastic, but it is incredibly expensive.
For the record, note that it is no big deal to take a UK rental car to the Continent for a day trip returning to the UK ... if for some reason you want to do that.
(Example, Sixt promoting the concept of a day trip! link )
Again, you would never do this for a longer tour: simply rent a car on each landmass. Enjoy!