how long travel from london to thailand by train,?

via moscow, Beijing and vietnam
how long would it take?

http://www.seat61.com/Thailand.htm#London%20to%20Thailand%20overland

A LOOOOOOOOOOOOOOOOONG Time
Better pack some reading material =]

just get a direct flight maybe??

A b!oody long time, why don't you want to fly it ? wouls it be easier to go by boat ? I don't know sorry x

as long as you like (or as long as your money holds out) ... friend of mine took 4 months over it, breaking the journey at a lot of interesting places ... no point in going by train if you're not going to explore en route

The site you've linked to, Seat61.com, gives you the answer: at least 3 weeks each way.

The route would be:
London - Brussels
Brussels - Cologne
Cologne - Moscow
Moscow - Irkutsk - Ulan Baatar - Beijing (there is no need to go all the way to Vladivostok! - Vladivostok is 4100 km beyond Irkutsk, and 1400 km from Beijing)
Beijing - Hanoi
Hanoi - Saigon / Ho Chi Minh City
Saigon - Phnom Penh (bus)
Phnom Penh - Battambang (train or bus)
Battambang - Thai border (bus) - Bangkok (train)

or you could go Hanoi - Vientiane (Laos) (20-24 hour bus ride) then train from Vientiane to Bangkok.

Whichever route you go, getting all the necessary visas will be a pain, since you will need transit visas for Belarus, Russia, Mongolia, China, Vietnam, and either Cambodia or Laos (assuming you're a UK citizen), and you have to apply for them in the right order... and if you enter overland you're only allowed to stay in Thailand for 15 days (30 days if you fly in).

I'm not quite sure how long it will take, but this could be the route you could take.

London to Paris
Paris to Berlin
Berlin to Moscow
Moscow to Vladivostok
Vladivostok to Beijing
Beijing to Ha Noi (Vietnam)
Ha Noi to Bangkok, Thailand

Your probably looking at about three weeks to a month if you don't want to explore all the destinations above. You also need to take into consideration the fact that it's going to cost an awful lot more than a regular £300 airfare direct from London to Bangkok.

If the whole point of going by train is so you get to see all these amazing places, you could still do that by plane. Just make lots of stop overs at some of those destinations on route to Bangkok. You'd still be able to visit most of them, but you'd be able to do it much cheaper. The train maybe eco-friendly, but its not the cheapest way to travel.

If you have the time (we're talking a minimum of 3 weeks one-way), you can travel from London to Bangkok overland. The links below cover travel in either direction, from London or to London:

Step 1: London to Moscow by train. Daily departures, 2 nights, from about £160 one-way with sleeper. Spend at least 1 night in Moscow.

Step 2: Moscow to Beijing by Trans-Siberian Railway Two trains a week, 6 nights, from about $450 one-way in 4-bed sleeper. Spend at least 1 night in Beijing.

Step 3: Beijing to Hanoi by train Two trains a week, 2 nights, about $150 or £75 one-way in soft sleeper. Spend at least 1 night in Hanoi.

Step 4: Hanoi to Saigon by train Several trains daily, 2 nights. Why not stop off to see Hue or Hoi An? About $80 or £40 one-way in soft sleeper.

Step 5: Saigon-Phnom Penh by bus Daily, 1 day. Spend at least 1 night in PP.

Step 6: Phnom Penh-Battambang by train or bus, bus to the frontier, train to Bangkok.

Too long! Just catch the plane !