From January, Eurostar will cut 20 trains each week between the British and Belgian capitals. On weekdays, there will be only seven daily departures in each direction, rather than the current nine.

Last month The Independent revealed that Eurostar planned to axe one departure in 12 because of falling demand between London, Paris and Brussels.

It now appears that the Belgian capital will take the brunt of the cuts.

Services from London St Pancras will still begin at 6.50am, but the 8.04am departure will be axed from January. The cancellation results in a gap of over two hours between Brussels-bound trains during the morning rush hour. Business passengers from outside London who are unable to reach the St Pancras terminus in time for the first departure will now not arrive in Brussels until the afternoon.

The evening rush hour has an even longer gap. Travellers who miss the 5.04pm train face a wait of two-and-a-half hours before the last service of the day, at 7.34pm.

Connection opportunities deeper into Belgium, and to Germany and the Netherlands, have also been reduced. London-Brussels trains also call at the city of Lille, with onward connections deeper into France.

Although 22 per cent of Anglo-Belgian services will be withdrawn, the total number of seats will not fall so sharply because of the introduction of higher-capacity trains.

The e320 trains hold 902 passengers, compared with 750 for the original rolling stock.

For the first time since the full Eurostar service began running, there will be more flights from Heathrow to Brussels than there are trains from London to the Belgian capital. British Airways operates five flights a day on the route, and Brussels Airlines has a further three.

Demand for travel to both Paris and Brussels has fallen sharply since the terrorist attacks in November and March respectively. In addition, the expected Brexit boost to inbound tourism to London because of the slump in sterling has not materialised. Last month hotels in the capital saw occupancy rates and revenue fall compared with October 2015.

The fall in demand is likely to be reflected in Eurostar’s earnings from passengers originating in Brussels and Paris.

One return trip to Paris is to be cut each working day: an afternoon departure from London, returning early evening from the French capital.

Eighty Eurostar posts are expected to be lost as a result of the cuts, though with no compulsory redundancies; staff are being offered voluntary redundancy or the chance to take a sabbatical.

The train operator is offering its lowest-ever fare, £19 one-way from London, for passengers who book through Facebook and are prepared to leave the departure time to Eurostar. Buyers of the “Snap” brand of tickets are told the specific train they must travel on 48 hours before they leave.

A spokesperson for Eurostar said: "We always monitor and adapt our timetable to reflect the time of year and customer demand. January and early February are traditionally a quieter time of year for us so over the past few years, we have reduced the number of services on our routes.