Fearful of damaging its lucrative tourist trade, the Turkish government has been keen to stress that the areas affected by the tremor are away from holiday destinations, and that it is perfectly safe to visit the country.
And, overall, the British tourist industry and its customers have agreed. Thomson, the UK's biggest holiday company, said none of its customers had been affected.
A spokeswoman said: "Our nearest resort to Istanbul is Kusadasi on the Aegean.
"No tremors have been felt and everyone is all right ... we are operating as usual." The Turkish tourist board pointed out that the main UK package holiday destinations of Bodrum, Fethiye and Marmaris, in the south of Turkey and some 500 miles from Izmit, the epicentre of the quake, were untouched.
The historic areas of Istanbul were also unaffected and the city's airport was open.
A team of British earthquake rescue workers, from the International Rescue Corps, were preparing to fly out yesterday. Also offering to help was the Gloucester-based charity Rapid UK, which has helped to find survivors after recent earthquakes in Colombia, Honduras, Georgia, Iran and Costa Rica.
The charity's director, Graham Payne, said: "We have sent out our offer which has reached the British embassy in Ankara and we are waiting for the green light.
"All the equipment is ready to go and although we were hoping to get the 5pm flight from Heathrow there are other flights tonight."
The Foreign Office said no Britons were reported to be killed or injured. The honorary consul in Bursa, one of the cities hit, could not, however, be contacted yesterday because of damaged telephone lines.
An emergency telephone advice line - 0171-839 1010 - had been set up for people anxious about relations or friends in Turkey.
Alan Flook, general secretary of the Federation of Tour Operators, said only about 100 British holidaymakers were thought to be in Istanbul. "Thankfully, the vast majority of Britons on holiday are well away from the danger area in the seaside resorts," he said.
The British consulate in Istanbul said about 1,600 Britons believed to be in the city were safe.
British engineers from Thames Water were caught up in the earthquake while installing a water system in Izmit. The company said that all 12 were safe but were helping to look for 24 Turkish colleagues.
Mike Price, one engineer, said he had been woken by a "great crashing and rumbling", and the sound of falling furniture. He said that the building he lived in and the firm's offices were earthquake-proof buildings, but much of Izmit was badly damaged. "We can see that a lot of people are injured and there is much devastation to buildings," he said.Reuse content