Option number one for vegetarians is to cook some shop-bought veggie burgers or sausages. If it's a ?bring your own meat' barbecue this is probably what vegetarians will bring. Now, some people hate meat substitutes, but most vegetarians quite like them, and will be quite happy with a veggie sausage, particularly with some good relish and salad in a bun.
Barbecued halloumi

However, there are lots of other things you can cook for vegetarians which will be a little more impressive - and more than likely the meat-eaters will like them too. Halloumi cheese is always popular, and very easy to cook. This is a firm cheese that doesn't melt when cooked, so you can slice it, or cube it and stick it on skewers, and cook over the barbecue until browned on the outside, and soft on the inside. If cooking on skewers, you could alternate cubes of halloumi with cooked new potatoes.
Grilling vegetables on a barbecue

Grilled vegetables are another good option, as they really taste of ?barbecue'. For something slightly unusual, try brushing thick asparagus spears with olive oil and grilling for about 5 minutes, until browned in places. You can also easily grill aubergine or sweet potato slices (1-2 cm) or courgettes (halved lengthways), having coated them in olive oil and seasoning. You can also grill whole aubergines on the barbecue, having pierced them in several places with a fork. When they are soft you can scoop out the inside and spread it on some bread, or use it to make an aubergine dip.

Wrapping vegetables in foil prevents charring, so is useful if your vegetables tend to burn on the outside but are raw inside. For an authentic barbecue taste though, it is a good idea to cook for a few minutes without foil at the end, until it looks char-grilled. This is one way of cooking corn on the cob, an essential part of any barbecue for meat-eaters and vegetarians.
Cooking vegetables with a barbecue ?wok'

Lots of other vegetables, such as mushrooms, peppers and onions, work well on a barbecue, but can be quite fiddly to work with. The classic option is to thread vegetable pieces on to skewers to make vegetable kebabs. A quicker way is to use a barbecue ?wok' or grill pan (try Lakeland), which you can place on top of the barbecue and keep all your vegetable pieces together. Then you can easily cook smaller vegetables without them falling through onto the barbecue, while retaining that barbecue flavour. This is also a simple way of keeping vegetarian food separate from meat.
Barbecue garlic bread

A good accompaniment for all your guests is to brush some slices of baguette or ciabatta with olive oil and seasoning, and grill on each side until golden brown. If you wrap a whole garlic bulb in foil and barbecue until the cloves are soft, you can squeeze the roasted garlic out of the cloves and spread it on the bread. Garlic roasted like this becomes much milder and sweeter.
Make your own veggie burgers for the barbecue

For the really ambitious, why not try making your own veggie burgers? Then you can have complete control over the ingredients and will feel very satisfied with your creativity. There are loads of recipes for different kinds of veggie burgers, but typically you could use mashed beans or lentils as a base, and add any kind of cheese, chopped onions, nuts, herbs or spices for flavouring, breadcrumbs to help make it a bit more solid, and beaten egg to help bind it. Then simply grill it! You may have to experiment to get a burger that doesn't fall apart too easily - if you are worried, start by cooking it on foil or a baking sheet, and finish up with a few minutes directly on the barbecue.