Since the deregulation of the energy industry, gas and electric supply can now be provided by a number of different companies, regardless of where you live in mainland UK. While it is not advisable to constantly chop and change energy suppliers, it is prudent to compare prices on a regular basis. Some companies will offer a discount if you use them for both gas and electric supply. Some energy companies will offer useful introductory discounts. Some energy companies will be cheaper for gas supply while other energy companies will be cheaper for electric supply.
In times of uncertain and possibly rising energy costs, it is also worth considering fixed price options offered by several energy companies. The advantage of a fixed priced deal for either gas or electric is you know in advance the amount that you will be paying and can budget accordingly. The disadvantage is that if energy prices fall below the fixed price you are paying, you will not benefit from the lower prices. If this does happen to you, it might be appropriate to consider switching energy companies to release yourself from the fixed price deal you are committed to. However, care should be taken to ensure you have considered any exit penalties that might be applied.