Failure to sweep your chimney regularly is detrimental to your safety and the efficiency of your flue.  A build-up of soot, tar and other unwelcome deposits can cause obstructions and restrict the release of exhaust gases (carbon monoxide) from your appliance or open fire.  Allowing soot, tar and other unwelcome deposits to form in your chimney can lead to chimney fires and potentially carbon monoxide poisoning.  Symptoms can include:

Severe headaches, chest or stomach pains, drowsiness, nausea, dizziness and general lethargy.

Carbon monoxide is colourless, odourless and causes 200 people in the UK to die or become seriously ill every year.  Have your appliance checked and chimney swept annually, install a carbon monoxide alarm and check it regularly.  For gas appliances use a Gas Safe registered engineer; for oil appliances use an OFTEC registered engineer, and for solid fuel (house coal, smokeless coal and wood) use a qualified chimney sweep registered with either the Guild of Master Chimney Sweeps, NACS or a sweep who has completed a City & Guilds accredited programme.