* Tour operator aims to restart Tunisia trips by Spring 2018
* CEO says travel to Turkey not impacted by Germany tensions
* Company reiterates full-year guidance, revenue up 14 percent (Recasts, adds detail)
LONDON, July 27 (Reuters) - Tour operator Thomas Cook will restart holidays in Tunisia now that Britain has softened its travel advice to the country, the firm's boss said on Thursday.
The move, which came as the company reiterated its full-year outlook, should be a welcome boost to Tunisia, where tourism accounts for 8 percent of gross domestic product and is a key source of foreign currency and jobs.
Britain said on Wednesday that it was no longer advising against travel to most of Tunisia after tightening its advice following a militant attack in a Tunisian resort in June 2015. There had also been an earlier attack at the Bardo museum in Tunis.
The attacks led to two years of sharp declines in tourism.
Thomas Cook Chief Executive Peter Fankhauser said that the British decision was unexpected and a positive for Tunisia and the tourism industry.
"The foreign office came to the conclusion that it is again safe to travel. We didn't have any programme for the winter so we are setting up a really good quality offer for Tunisia and this is going to take some time," he told reporters.
"I suppose that we are going to start during the winter season, but more towards the spring."
Tour operators such as Thomas Cook have seen business in the Middle East and North Africa suffer in recent years as security issues deterred visitors, with travel firms laying on more holidays to the western Mediterranean to compensate.
However, this year has seen a bounceback in markets such as Turkey and Egypt, while markets such as Spain have been more thorny.
Fankhauser said that a resurgence in Turkey had not been affected by increased tensions with Germany, and said that Turkey remained attractive despite a warning by the German government for its citizens to be careful when traveling there.
On the flipside, the increase in capacity in Spain is hitting margins there, and Thomas Cook said that prices were under pressure from the intense competition.
The tour operator said that strong demand for summer bookings would continue into winter, adding that its full-year operating profit would be in-line with forecasts.
Profit is expected to grow 6 percent to 326 million pounds for the financial year ended Sept. 30 2017.
The travel firm said that group revenue was up 14 percent, and that winter 2017/2018 was 30 percent sold, with bookings ahead in all markets. Shares were up 3.1 percent.
Credit Suisse said that the revenue growth was the strongest for "many years" but said that the continued margin pressure meant that it was leaving its overall estimates broadly unchanged. (Reporting by Alistair Smout Editing by Jeremy Gaunt.)