Eating out with vegans
Disclaimer: the information on this page is UK-specific - if you're from elsewhere some of this information may not apply to your country (e.g. baked beans and McDonald's fries are not universally vegan), but if you are visiting the UK I hope you will find this page useful. Have a look at HappyCow and Veggie Heaven to find vegan-friendly restaurants and shops in the places you'll be visiting.
Restaurants
If you're going out for a meal, having a vegan in the group doesn't mean you have to go to an all-vegetarian restaurant to accommodate them.
Many world cuisines don't rely on dairy products or eggs and have at least some vegetarian options that are vegan by default. Types of restaurants most likely to have vegan options on the menu include Indian, Chinese, Thai, African and Middle Eastern. A couple of things to watch out for: in Indian restaurants check that they cook with vegetable oil rather than ghee (clarified butter) and in Thai restaurants check that they don't put fish sauce in the vegetarian dishes. I've found that of these, Indian restaurants generally have the greatest choice of vegan dishes. Chinese and Thai places will often leave the egg out of otherwise vegan dishes and swop egg noodles for rice or wheat noodles if asked. Italian restaurants might be able to provide a vegan dish but it's worth checking with the restaurant in advance if possible. Seemingly vegan dishes such as pasta and tomato sauce might be made with egg pasta, and even if they're willing to make a cheeseless pizza the base might have eggs in.
Traditional pubs and cafes aren't usually the most promising of places for vegans. The type of pub where the menu consists of five different roast meats and a 'Vegetarian Option' (often unspecified - it's like walking into a restaurant and saying "I'll have the food, please" and seeing what happens) will likely serve something cheese-laden as the non-meat dish. Some places with a more extensive menu might serve a vegetable curry or chilli or similar - again, read the menu before you go in if possible. Other than that, they'll probably serve jacket potato with baked beans, which is usually the default vegan option in traditional cafes.
Mainstream chain restaurants often have menus and special diets information online, so check the website if you're planning to go to one, or have a look at the chain restaurants page to see if I've got there first.
Finally, there are some very good vegetarian and vegan restaurants and pubs out there with varied menus (it's not just lentils and nut roasts, you know!), particularly in large cities, so if your group of friends or relatives aren't particularly hardcore carnivores you could always give one a try. Have a look at HappyCow or Veggie Heaven to find one in your area.
If you're still unsure about which restaurant to choose, ask the vegan(s) in your group for some suggestions!
Lunch on the go
'Just grabbing a sandwich' often isn't an easy option for vegans, but takeaway lunch is possible with a bit of effort. Although until mainstream shops get their heads round the concept of vegan sandwiches it is generally easier for vegans to carry a packed lunch when possible...
Chain sandwich shops and supermarkets are generally rubbish at providing vegan options. They either seem to think that the only non-meat sandwich fillings are cheese or egg, or (even more annoying) they make almost-vegan sandwiches or wraps such as spinach and avocado salad sandwich, spicy mixed bean wrap or houmous and roasted vegetable wrap and then add a small amount of some dairy product or other as a garnish.
However: Pret A Manger do a nice vegan houmous salad sandwich and some larger Boots sometimes stock vegan sandwiches. Some Holland and Barrett shops stock vegan sandwiches and pasties. Subway will do a sandwich stuffed full of various types of salad (although they might look at you a bit funny when you ask). Cranks make some nice vegan sandwiches, if you can find anywhere that stocks them.
If you can find a vegetarian wholefoods shop they sometimes have a deli counter. Small independent sandwich shops with decent menus (not just the five-types-of-roast-meat places) are a better bet for vegan options, often they will offer at least houmous sandwiches. If you or a vegan friend are really stuck for a sandwich, my standby option usually involves buying bread rolls, a pot of houmous and a bag of salad for a DIY sandwich.
Surprisingly, Burger King can be a standby option for a takeaway vegan meal - their bean burger is made from entirely vegan ingredients if you ask for it without the cheese slice. However, they do say on the menu that the burger may be fried in the same oil as chicken and fish products, which not all vegans will find acceptable and is certainly not ideal. The fries are also vegan. McDonald's fries are vegan (in the UK but not in all countries) but none of their burgers are (although some vegans would choose not to hand over their cash to McD's in any case).
The default option in motorway service stations, airports and other 'food village'-type places is often the traditional jacket potato with baked beans (or maybe vegetarian chilli if you're lucky). Service station M&S food places have recently started stocking a range of vegan rice/pasta salads, which is a step forward. Maybe one day they'll even stop putting butter in their houmous and roasted veg sandwiches... Or if all else fails, fill up on a portion of chips or fries or the Burger King beanburger. Not that I recommend that anyone should live on chips, but it's better than going hungry. Talking of chips, the widespread availability of the British Chippy is provides very useful standby option for a quick stop-you-being-hungry sort of meal. Get some mushy peas too and you've even got a serving of iron and protein in your meal - although I wouldn't go as far as to say that tomato ketchup counts as a portion of fruit and veg...