A hybrid bike is a mixture of a road bike and a mountain bike. This means it can perform well on the road but also it can cope off-road when needed. This combination makes hybrid bikes especially useful for an everyday commuter bike (also known as a city bike) as they deal well with potholes and gravel paths without the added weight of a mountain bike. They remain efficient enough for a long commute and often come with pannier racks and sometimes mud guards which can be useful when commuting. Hybrid bikes can also make good touring bikes if you are planning an adventure.
Hybrid bikes are cheaper that more specialised mountain bikes and road bikes because they do not have suspension like mountain bikes or super lightweight components like high-end road bikes. For this reason, you can get a decent hybrid bike from between £400 & £1,500.
In our opinion a hybrid bike should not have suspension. A hybrid bike will be used mainly on the road but have the capability to ride off road when needed. The off-road capability usually comes from higher volume tyres than a standard road bike.
There are some great hybrid bike deals to be had on the following websites.