British tourists are warned against all travel to Istanbul

The Turkish tourism industry was in crisis yesterday after the British Foreign Office and other governments warned their nationals against travelling to Istanbul.

Jack Straw, the Foreign Secretary, told the House of Commons there was "a significant threat from terrorism" in Turkey and all but the most essential travel to the country's largest city should be avoided "until the situation becomes clearer".

Hundreds of British tourists with tickets to travel to Turkey face uncertainty over whether they will be able to claim refunds from tour operators because the Foreign Office stopped short of issuing a general warning against travel to all parts of the country.

The Association of British Travel Agents (Abta) said its members would offer travellers to Istanbul the chance to rearrange or claim refunds on their holidays because the Foreign Office was specifically warning against travel to the city, but travellers to other Turkish destinations would have to travel as normal.

Frances Tuke, an Abta spokeswoman, said: "As it stands, the people travelling to outside Istanbul will not be entitled to refunds or rearrangements because there has been no specific warning outside Istanbul. We rely very much on the Foreign Office advice."

Abta estimated that only about a hundred package holiday tourists are in Istanbul, with an unknown number of independent travellers.

The spokeswoman said: "It is not the most popular time to be in the country at the moment. The weather is about the same as in England at this time." She said most of those currently in Istanbul would return on their scheduled flights, explaining: "We have looked into the possibility of getting people back early but the reality is most people are on short breaks and it is not practical ... to shift them on to others."

British Airways, which operates twice-daily return flights between London and Istanbul, delayed the departure of its Istanbul-bound 10.10am flight from Heathrow for half an hour yesterday. The flight was later allowed to depart but the airline said it would reconsider its schedule in the light of the Foreign Office warning. The British Foreign Office warned that its consulate in Istanbul, the target of one of yesterday's blasts, would "not be able to provide the full range of services" until further notice.

The German and American governments also upgraded their security warnings for the country. American travellers were warned to avoid "Western-oriented businesses, religious institutions, shopping centres, restaurants, bars, etc" and to "exercise extreme caution" throughout Turkey. Germany, which has about two million Turkish immigrants, advised its citizens to delay travel.

Although there are relatively few tourists in Turkey at present, yesterday's blasts came about a month before the peak booking time for package tours and threaten to wreck one of the most important sectors of Turkey's economy.

The country receives about 13 million tourists every year and makes about £5.25bn a year from the sector. Turkish tourism officials aimed to increase the number of visitors to 25 million in 2010 and increase revenues to £12.5bn but a bombing campaign could bring the industry to its knees.