14/03/2012 10:59 GMT | Updated 14/03/2012 16:26 GMT

White Cliffs Of Dover: Stretch Of Famous Landmark Crumbles Into Sea (PICTURES)

A large section of the White Cliffs of Dover has crumbled into the English Channel following a "substantial" rockfall, the Coastguard has said.

Tonnes of chalky cliff-face sheared off near an area known in the Kent port town as Crab Bay, but no-one was injured.

Dover Coastguard said a full survey has yet to be carried out to determine the exact amount and length of cliff that crumbled on Friday.

The collapse may have been caused by rain freezing after being absorbed into the chalk and then expanding, causing it to weaken.

A Dover Coastguard spokesman said: "We can see the start of it from where we are based but then it goes round the corner.

"It appears that it crumbled from the top at high water so there was no-one down below at the time. It was quite a substantial fall.

"No-one was injured but it does serve as a reminder that if people are walking along the cliff-top or underneath, that the cliff can crumble away.

"Over the years and around the country, including along the coast at Beachy Head in East Sussex, cliffs can fall after water expands when there has been freezing conditions."

White Cliffs of Dover

The Kent landmark, popularised by Dame Vera Lynn's wartime song The White Cliffs of Dover, has suffered large rockfalls before, most significantly in January last year.

When the cliffs tumble, locals describe it as "like a lorry going down the hill".

Sam Wydymus, 40, co-owner of the nearby Coastguard pub, said: "I have seen pictures of the rockfall and the most noticeable thing is you can see this big patch of white on the cliff-face.

Tonnes of chalk from the White Cliffs tumbled into the sea

"We didn't hear anything when it fell but it was big enough for people round here to be talking about it. The last major cliff-fall was in January last year when every emergency service turned up.

"That happened during the day and was quite scary, with people screaming on the beach saying it had fallen. When the cliff does fall, it is quite muted and sounds like a lorry going down the hill.

"There isn't any physical warning beforehand. When it happens, it just happens."

Take a look at some of Britain's most famous cliffs, well known for their white profile as well as their important coastal position.

Positioned at the narrowest part of the English Channel, the white cliffs of Dover were not only the first form of defence for the UK, but also were often the last sight seen by sailors when leaving the country.