There is an article regarding the possibility of a Vigo to UK route on www.portseurope.com I can't add the link right now but you can go to that website and search VIGO.
Vigo has been connected to the United Kingdom on at least two occasions by ro/ro passenger and freight services.
During the late 1970's to early 1980's the Spanish shipping company Naveiras Suardiaz operated a weekly freight only service from Southampton to Vigo
From from June 1966 to September 1966 the Norwegian shipping magnet Knut Kloster (the co founder of NCL Norwegian Cruise Line) operated the ferry SUNWARD on a short lived weekly ferry service Southampton-Vigo-Lisbon-Gibralter-Lisbon-Vigo-Southampton under the Kloster Sunward Ferries name.
The route was short lived for various reasons, Wikipedia has a page dedicated to the SUNWARD for anyone unfamiliar with this vessel.
Portsmouth to Vigo is 654 nm, at an average cruising speed of 20/21 knots the journey time is One day and 7 hours.
Portsmouth to Gijon is 518 nm, at an average cruising speed of 20/21 knots the journey time is One day and 1 hour.
Vigo is a very busy car export/import port with several quays for large ro/ro vessel's including one fixed linkspan and 2 soon to be 6 concrete ramps for large ro/ro vessel's.
Vigo is the base of Spain's largest trawler market and is Spain's leading fishing port, it also has a large industrial base, it has great motorway and rail connections to the rest of Spain as well as to nearby Portugal where the border is less than 24 miles away. Vigo is also close to the famous and popular UNESCO world heritage site at Santiago de Compostela which is under an hour away.
As much as I would like to see a Portsmouth to Vigo route the economics don't stand up against a possible Portsmouth to Gijon link.
What I would love to see is a four night voyage from Portsmouth to Lisbon. (I know that I'm dreaming)
Portsmouth to Lisbon is 870 nm, at an average cruising speed of 20/21 knots the journey time is One day and 17 hours.
If Britanny Ferries decided to take the opportunity of advertising Portsmouth to Lisbon as a mini cruise along with the passenger and freight it would be an excellent route for the whole of the Atlantic coast of the Iberian peninsula as far down as Andalucia and Gibraltar and also eastwards to central Spain.
A schedule could look similar to this.
Sunday Portsmouth depart 18.00
Two nights at sea.
Tuesday Lisbon arrive 12.00 local time
Tuesday Lisbon depart 18.00 local time
Two nights at sea.
Thursday Portsmouth arrive 12.00
Thursday Portsmouth depart 18.00
Two nights at sea (the possibility of going via Cherbourg for a crew change if needed)
Saturday Bilbao/Santander arrive 08.00 local time
Saturday Bilbao/Santander depart 13.00 local time
One night at sea.
Sunday Portsmouth arrive 14.00
It's a shame that Brittany Ferries don't take the opportunity to alter the building process of the SANTONA with an additional deck above the bridge with balcony accommodation, a pool area and a gym/fitness center making her more durable for a longer crossing to either Lisbon or Vigo.
In 1969 (P&O) Normandy Ferries ran a seasonal winter service from Southampton-Lisbon-Casablanca-Lisbon-Southampton with the LEOPARD.
In 1970 the brand new EAGLE was delivered to the General Steam Navigation operating as (P&O) Southern Ferries and she started a year round weekly 6 night round trip Southampton-Lisbon-Tangier-Lisbon-Southampton with Algerciras added in 1972.
The route ended in September 1975 after industrial action by the seaman and the EAGLE was quickly sold to the French company Navigation de Paquet and renamed the AZUR.
FYI the former EAGLE is still in service after 49 years sailing for the Russian company Black Sea Cruises as their sole cruise ship named KNYZ VLADIMIR based in Sochi, Russia.