Airlines flying between London and Paris are generally domestic airlines such as British Airways and Air France that serve long-haul transit passengers rather than those traveling from city center to city center. Most travelers from Australia and New Zealand choose to fly to France via London, although most airlines can add a route to Paris (or any other major city in France) to their Australia / New Zealand to Europe ticket. Traveling between England, Paris and northern France is so easy that it's surprising how long-distance tourists don't combine the UK and France for a two-hub holiday.
It only takes 2 hours and 15 minutes to get to Paris by Eurostar train, so if you leave early, many people can take a day trip to Paris. Standard fares from London to Paris or Lille start at £72 (£99 to Avignon) and are non-refundable; the number of seats is limited, so it is best to book as soon as possible. The France-Italy Pass provides two months of unrestricted train travel for four days. The fare for adults in second class is 203 to 309 Euros, or for two months for up to 10 days, the fares are 340 to 521 euros.
But you don't need to travel from Paris to London to use these trains. Eurostar also has high-speed direct trains from Lille in northeastern France to Ashford and Ebbsfleet in Kent - starting points for superb South East England tours - before arriving in London. And if you don't mind transfers, Eurostar can arrange connecting flights via Ashford, Kent, between the entire UK rail network and French destinations such as Caen, Calais, Reims, Rouen and Disneyland Paris. Of course, if you're a traveller from Scotland or perhaps Liverpool, then flights may still be the better option.
But how long does it take, or should I just take a bus? While Eurostar trains will take you from city center to city center in just over 2 hours, faster buses using the England-France tunnel instead of ferry crossings take 7.5 hours. The fastest time of around 7.5 hours is much longer compared to 2 hours for Eurostar trains. For most travelers looking to travel between central London and Paris, the killer fact is that Eurostar trains will likely arrive in central Paris around the time a similar routed flight would prepare to depart.