Residents were evacuated from their homes as dozens of firefighters tackled a major fire in north-west London this evening.
A 75-metre hazard zone was set up around a burning air conditioning workshop behind a row of houses in Harrow, amid fears gas cylinders at the site could explode.
A video from the scene showed the single-storey warehouse engulfed in flames.
Some 58 firefighters and eight fire engines were battling the blaze in Headstone Road for several hours, after the building went up in flames at about 3pm.
Record producer Chris Andoh, 24, whose house is opposite, said: "It all started with heavy smoke, you couldn't see any flames at first.
<blockquote class="twitter-video" lang="en"> <p dir="ltr" lang="und"><a rel="nofollow" target="_blank" href="https://twitter.com/HarrowObserver" class="body-link" data-vars-item-name="BL-2927521-https://twitter.com/HarrowObserver" data-vars-event-id="c23">@HarrowObserver</a> <a rel="nofollow" target="_blank" href="https://twitter.com/hashtag/fire?src=hash" class="body-link" data-vars-item-name="BL-2927521-https://twitter.com/hashtag/fire?src=hash" data-vars-event-id="c23">#fire</a> <a rel="nofollow" target="_blank" href="https://twitter.com/hashtag/harrow?src=hash" class="body-link" data-vars-item-name="BL-2927521-https://twitter.com/hashtag/harrow?src=hash" data-vars-event-id="c23">#harrow</a> <a rel="nofollow" target="_blank" href="https://twitter.com/hashtag/headstoneroad?src=hash" class="body-link" data-vars-item-name="BL-2927521-https://twitter.com/hashtag/headstoneroad?src=hash" data-vars-event-id="c23">#headstoneroad</a> <a rel="nofollow" target="_blank" href="http://t.co/lmCi0MMMjU" class="body-link" data-vars-item-name="BL-2927521-http://t.co/lmCi0MMMjU" data-vars-event-id="c23">pic.twitter.com/lmCi0MMMjU</a> — C.Andoh (@ChrisAndoh) <a rel="nofollow" target="_blank" href="https://twitter.com/ChrisAndoh/status/639838948102144000" class="body-link" data-vars-item-name="BL-2927521-https://twitter.com/ChrisAndoh/status/639838948102144000" data-vars-event-id="c23">September 4, 2015</a>
"[Then] flames started to blaze through the building's roof as well as the sides - literally right next to someone's back garden.
"They advised everyone to stay indoors towards the back of their homes as there are gas cylinders within the building which they are trying to contain in case of an explosion."
The London Fire Brigade said police helped to evacuate people from homes within the hazard area.
Builder Vlad Grigoras, who working at a school nearby, said: "Police were blocking more and more roads on a larger area and buses got stuck on the main road, people were walking home.
"It feels like that the firemen have quite a job on their hands as they brought around 10 fire engines and they were pumping water through hoses from a long distance."
An LFB spokesman said: "Crews believe an acetylene cylinder is involved in the blaze so a 75-metre hazard zone has been put in place as a precaution, as these cylinders can sometimes explode when exposed to heat.
"The fire is producing a lot of smoke in the local area so we would advise people living and working nearby to keep their doors and windows closed as a precaution."
The cause of the fire is not yet known.
