Each weekday from 27 October, 30 Flybe flights will fly to or from the Docklands airport / PA

Flight from London to Exeter could cost as little as £23 – which is up to £95 cheaper than the rail fare

Stay in bed in Devon an hour longer, arrive in London 40 minutes earlier and save £95 on the train fare - that is the offer to the citizens of Exeter by Britain's biggest regional airline.

Flybe has signalled an autumn fares war on domestic travel, against both rival airlines and the train operator First Great Western. The airline, which is based in Exeter, has launched a new network of flights connecting cities in Britain and Ireland with London City airport (LCY).

Each weekday from 27 October, 30 flights will fly to or from the Docklands airport. Flybe will launch four daily flights to Edinburgh and Dublin, competing with British Airways and CityJet respectively.

There are currently no air links covering the 150-mile distance between Exeter and London, but Flybe claims its timings – with a departure at 6.40am, arriving in the capital at 8am – will entice business travellers from First Great Western. Advance tickets on the first flight from Exeter suggest a fare as low as £23, compared with £118 for an Anytime ticket on the first train of the day – on which Advance fares are difficult to find.

Flybe is also re-launching services to London City from Belfast (three times a day) and Inverness (twice daily). All flights come with a timekeeping promise: “If you arrive more than 60 minutes late, due to reasons within our control, we’ll give you a £60 flight credit.”

Flybe’s chief executive, Saad Hammad, rejected the suggestion that the move could lead to an all-out battle on price: “I’m not expecting kamikaze behaviour from the competitors. Our sense is that there is enough demand on these routes. We are the champion of the regions.”

A spokeswoman for British Airways said: “We always welcome competition and believe that we offer our customers travelling from London City airport a great service and value for money.”

London City’s chief executive, Declan Collier, said: “Flybe will bring an immediate uplift of up to half a million new passengers to the airport. In addition, Flybe’s selection of routes serves to cement further LCY’s status as the business traveller’s airport of choice.”

The airline says that it will also launch off-peak leisure flights from London City to ski airports, provincial airports in France and destinations in northern Spain.