An earthquake with a magnitude of at least 4.7 has shaken householders in parts of Kent.
The fire service has received calls from people in the Deal and Folkestone areas reporting large cracks in house walls and chimneys falling down.
The tremor at 0818 BST, which lasted a few seconds, was felt as far afield as Essex, East Sussex and Suffolk.
Eyewitness Lorraine Muir said: "We've been evacuated by the Sally Army, we've got no gas or electricity."
A website for the US Geological Survey, which monitors earthquakes, said the tremor had a magnitude of 4.7.
It believes the epicentre of the tremor was located 15 miles (25km) south of Canterbury and had a depth of 6.2 miles (10km).
A Eurostar spokesman said everything was "running normally" on the Channel Tunnel.
Sharon Hayles, from Stanford near the Eurotunnel terminal at Folkestone, said her house slid from side to side for about 10 to 15 seconds.
Violent shaking
Another Folkestone man told BBC Five Live Breakfast that his whole house "shook quite violently".
Paul Smye-Rumsby, who lives in Dover, said: "It was about 08.15 when suddenly the bed shook violently.
"I thought my wife had got cramp or something but then I saw the curtains were moving and the whole house was shaking. It lasted about 1.5 seconds.
"All the power is off and we have got the portable radio on. People are standing outside talking to each other about it."
C'mon, now is not the time for humor! :O)
But that's good material, nonetheless...
That’s really something jdm.
Living in California in the USA for most of my life; I don’t really get excited about earthquakes unless it’s around the 6.0.
My husband said probably in this earthquake, you have to be concerned with the brick buildings.
First, what does "got cramp" mean? Second, I wish I had an inner clock that measured in .5 seconds!