London - Helsinki (Train + Ferry)
Fancy travelling between the United Kingdom and Finland without flying? Well the journey isn't easy, but it's certainly do-able. In total, the journey takes around two days (after you've included waiting times), with six different legs in total.
An alternative would be to travel via Russia, catching a train from Paris to Moscow, Moscow to St Petersburg, and then St Petersburg to Helsinki. However, this route would require additional visas for travel in Moscow, which would have cost implications.
Each leg of the journey will need to be booked separately, although you may be able to buy a ticket between London and Stockholm using the link below. In total, the cost of this journey would be around €200, although this is based on choosing the cheapest accommodation options, and excludes any special offers that may be available.