Could the departure boards from London St Pancras International see new destinations? That is the hope of station and rail link operator London St Pancras Highspeed and the owners of the Channel Tunnel, Getlink.

At present, Eurostar is the only passenger train service through the tunnel, a monopoly it has enjoyed since services began in 1994.

What’s the story at St Pancras?

Eurostar runs trains to Lille, Paris, Brussels, Rotterdam and Amsterdam. Since Brexit, the number of destinations it serves from London has shrunk, with Eurostar abandoning routes to the Mediterranean, the French Alps and Disneyland Paris.

Train calls at two stations in Kent and Calais on the French coast have been cut due to the additional red tape the UK negotiated after leaving the European Union.

The British demand to be subject to the EU’s new Entry/Exit System has severely limited the number of passengers that can be handled.

All of this is bad news for the track and tunnel operators. The 68-mile HS1 rail line from London to the Channel Tunnel has plenty of spare capacity, as does the 31-mile undersea link itself.

Who are London St Pancras Highspeed and Getlink?

London St Pancras Highspeed is simply the brand name used by HS1 Ltd, which has the concession to run the line from London to east Kent through to 31 December 2040. It earns money from the current Eurostar and Southeastern trains. The more trains that run, the more cash it makes.

Getlink was formerly Groupe Eurotunnel. It is the French firm that runs the Channel Tunnel and operates the LeShuttle car- and coach-carrying trains between Folkestone and Calais. Getlink charges around £20 per passenger carried through the tunnel – is keen to extract more from its expensive asset.

Surely it’s the green way to go?

Yes. Gwendoline ​Cazenave, chief executive of Eurostar, says: “Eurostar is committed to being the most sustainable form of international travel when it comes to carbon emissions. On average, the carbon footprint of travelling on our trains is 95 per cent less than flying.”

Mark Smith, the international rail guru known as The Man in Seat 61, adds: “90-95 per cent of Eurostar trains arrive on time or within 15 minutes, competing short-haul flights typically manage only 65-70 per cent by the same standard.

“From central London to central Paris, Eurostar is faster than flying, as well as more comfortable and convenient.”

Is there room for more?

St Pancras International was never designed with the expectation that British passengers would need to have facial biometrics and fingerprints taken before a trip to France and beyond. Eurostar has been capping capacity on trains to avoid excessive crowds at its London hub. But the station owner believes it can increase passenger throughput from the current maximum of 2,200 per hour to nearly 5,000 per hour – “in a bid to unlock the untapped potential of the iconic London station and high-speed line”.

Eurostar says: “In preparation for the upcoming European Entry/Exit System (EES), we have significantly invested in border capacity, doubling our processing capability to ensure even greater efficiency in 2025 and beyond.”

The cunning plan from London St Pancras Highspeed: Eurostar will add services, and new operators will move in.

“Several companies have expressed an interest to run international train services on HS1,” says London St Pancras Highspeed. “We are considering their needs and the potential for much greater foot traffic at St Pancras Station as we develop longer-term asset plans.”

Evidence from the thriving high-speed network in Spain suggests fares will fall, standards will improve and far more people would choose the train if competition is allowed to flourish.

Spanish start-up company Evolyn and Sir Richard Branson’s Virgin Group are developing proposals for rival services.

Where would new services go?

Initially any new operator will compete to and from Paris. Eurostar is making record profits thanks to its monopoly. Booking three days ahead, the cheapest London-Paris train fare is £109 – three times more than easyJet and Vueling from a range of London-area airports.

There is plenty of demand for low fares. Initially Eurostar all but killed off flights between London and Paris, but the number of daily departures between the English and French capitals is now back to levels last seen in 1994 before the Channel Tunnel opened – largely as a result of high prices.

What about further afield?

Robert Sinclair, chief executive of London St Pancras Highspeed, talks of “new destinations unlocking the potential of a fully connected Europe”.

Getlink says direct trains could run from London to:

The tunnel owner’s chief executive, Yann Leriche, said: “We are keen to drive forward attractive opportunities for low-carbon mobility with a range of new destinations in Germany, Switzerland and France.”

There is even talk of a route to Milan in Italy.

Will it ever happen?

Channel Tunnel rail services were always intended to range far more widely than simply a shuttle from London to Lille, Paris and Brussels. Granted, we have seen the welcome extension of some trains to Rotterdam and Amsterdam. But there are far fewer routes than originally intended, and far fewer passengers than envisaged.

Having London – the largest city in western Europe – as the UK hub should be a key advantage. Many people would prefer to travel by train to nearby foreign destinations.

What are the obstacles?

Standards on rolling stock used through the Channel Tunnel are rigorous and expensive to meet. Eurostar has retired some trains but these have been scrapped rather than sold on.

Even if a supply of trains can be procured, the next problem is finding a commercially viable market. In any rational world, Cologne – and nearby Dusseldorf – would be natural routes from London.

But even with simple one-change connections at Brussels and a journey time as low as 4h10m, few travellers bother: nine daily flights link each German city with London.

Booking three days ahead, the cheapest flight is £34; the lowest train fare, £211.

To more distant destinations, including Milan, the hurdles look even higher. No fewer than 35 flights from London serve the three airports in the Italian business capital, taking around two hours. A train would take at least nine hours.

Could direct trains ever run from other UK cities direct to Continental Europe?

Hundreds of millions of pounds were spent on trains and infrastructure to allow direct trains from Scotland, northern England and the Midlands to run to Continental Europe.

Routes such as Edinburgh to Paris and Manchester to Brussels were timetabled. But they never happened.

None of the kit was ever used as intended. The opening of the undersea link in 1994 was immediately followed by the surge in budget flying, with easyJet and Ryanair offering cheap and quick international flights.