Planning

Now that you have decided to come to the UK, it's time to get organised. Here are some handy tips:

Eight weeks before you go

Check that your passport is valid and will remain valid for the duration of your trip.
Find out which visas you need for each country you intend to visit and apply for them in advance. Leave yourself plenty of time to do this, as some embassies can take up to six weeks to issue visas (especially Working Holiday Visas).
Visit your doctor and arrange for any vaccinations (and medication) you need for your travels. Don't forget to ask for a vaccination certificate (you will need this at immigration checkpoints in countries such as Cambodia).

Hand in your notice at work and, if you intend to get a job whilst you are away, ask your boss for a written reference.
Tell your landlord you are moving out and, if you have been a good tenant, ask for a written reference. This will help you rent a property in the UK.
If you have a student loan, contact the student loan office and tell them you are going travelling. They will (probably) defer your payments until you return.
Ask your bank if they have a reciprocal banking arrangement with the UK. If they do, then open a bank account before you leave.
Check the expiry dates of all your debit and credit cards. If your cards are going to expire whilst you are away, get them replaced before you leave. If you have a number of debit/credit cards, take only the major ones with you - Visa, Master Card or American Express.
Ask your car insurance company for a no claims letter. This may help you get cheaper car insurance in the UK.
Apply for an international driving licence.
Appoint a power of attorney. It is vital to appoint a power of attorney if you want someone to deal with your finances whilst you are away. You can appoint someone by writing a letter stating that you give authority to a specific individual (such as a parent) to act on your behalf - you should also inform the bank, and anyone else who may require your signature whilst you are away, that you are appointing someone to act on your behalf whilst you are overseas.

Have a dental check-up.
Buy travel insurance.
Go shopping for a backpack/suitcase, and consider buying a smaller bag which you can use on day-trips.
Book accommodation. You should (at the very least) book your first night's accommodation in advance - especially if you're arriving during the summer months or at Christmas.

Contact utility companies (e.g. electricity, gas, water, cable TV, and telephone) and arrange to settle your bills.
Contact the Post Office and ask for your mail to be re-directed.
Open a roaming email account - Yahoo is very good.
Update your CV (resume) and make sure you have two referees (one professional and one personal) that can be contacted via email or fax.
Send a copy of your CV to your roaming email account for safekeeping.
Photocopy your passport, insurance and plane tickets. Leave one photocopy at home and keep another copy with you (but in a different bag from your original documents).
Leave a copy of your itinerary with a close friend or relative.
Pack. Remember, if you intend on working in the UK, bring something smart to wear, ideally a suit, but a shirt, tie and smart trousers or a skirt and blouse will suffice. Plus, add a change of clothes to your hand luggage in case your bags don't arrive with you.
Label your luggage inside and out and if you can, personalise it - you'll be surprised at the number of people with a backpack identical to yours.
Remove old destination tags from your bag.