When did you last have the flue swept? Has it been tested for smoke integrity to ensure that no cracks or faults have developed? Are dangerous gases able to escape?
‘If you have a gas-flame effect fire or an occasional solid-fuel fire, you should have your chimney swept once a year. If it’s in daily use, you should have it swept twice a year,

As a chimney is essentially a household exhaust pipe — funnelling away soot, smoke, gases, hot ashes and sparks — sweeping should be an essential part of home maintenance. It is no longer a job that ushers forth black clouds of soot ready for Victorian housemaids to clean up.
A modern, sealed sweep ensures that your flue is safe and unclogged by bird nests, soot build-ups and any other debris that might have dropped down from the chimney pot. Just as a roof tile may dislodge, so a chimney lining can deteriorate, exposing mortar joints and brickwork to corrosion and, ultimately, collapse. The older the house, the greater the risk.

A common misperception is that only chimneys servicing solid-fuel fires require sweeping, but even with a gas-flame effect fire, if a new appliance is being installed in a chimney previously used for solid fuel, it should be swept beforehand.Gas Safe Register (GFE) recommends that any gas appliance is safety checked at least once a year.
‘With GFEs, we’re making sure the chimney is drawing properly,’ says Willis. ‘Unfortunately, you can’t see or smell carbon monoxide.
‘The long, yellow flames of a gas fire are very different from the short blue flames of the gas you cook on. The yellow flames look lovely, but represent “incomplete burning”, so lots of nasties come off the top of the flame, which must be drawn up the chimney.’

Chimney sweeps are traditionally associated with good luck. In central Europe, ornamental sweeps are attached to flowers or confectionery as a New Year present — perhaps, in the coldest of climes, as a reminder of the importance of keeping your chimneys in tip-top condition.