* Over 20 pct of shareholders vote again directors' remuneration
* Tour operator sees bookings rise
* Reaffirms guidance despite cautious tone (Adds shareholder rebellion over executive pay)
By Alistair Smout
LONDON, Feb 9 (Reuters) - Shares in Thomas Cook fell more than 8 percent on Thursday after the tour operator issued a cautious trading update and saw more than a fifth of its shareholders rebel over its executive pay policy.
Among the 21.7 percent of shareholders that rejected the pay deal for directors was Standard Life Investments, one of the company's top shareholders.
The biggest revolt though was over an alternative payment plan for executives, called SSIP, which was rejected by over 30 percent of shareholders, who said its goals were unclear.
The company said the plan would not be used in the next year, and would not result in management receiving higher payments than they would in the regular remuneration policy.
"It is clear that there remain concerns about the level of information around the possible strategic objectives and the size of the maximum potential award," the company said in a statement after its annual general meeting.
It said it would now consult shareholders on the objectives of SSIP before any future implementation of the policy.
The travel company, originally founded in 1841, produced solid first-quarter results and a rise in summer bookings, but struck a cautious tone on its full-year outlook.
Security issues continued to hamper demand for holidays in Turkey, while Britain's vote to leave the European Union, which has depressed the value of sterling, had also reduced clarity about the rest of the year.
"We have made a solid start to the year, but it is still early days, and we remain cautious, given the uncertain political and economic outlook around the globe," Chief Executive Peter Fankhauser said.
Traders said that the company's cautious outlook was behind the steep fall in its shares, which were down more than 8 percent by 1435 GMT, after falling as much as 9.5 percent and erasing gains made over the two weeks leading up to the results.
Other aspects of the company's update were reassuring, the traders said. Summer bookings were ahead of last year, after the company responded to the security turmoil of 2016 by expanding its presence in Greece, Portugal and Croatia, which are less affected by security concerns.
Thomas Cook said that 31 percent of its summer holidays had already been sold, with bookings 9 percent ahead of last year.
"We are holding numbers but remain unenthused by the investment case and, in our view, that the basic business model continues to face structural challenges," analysts at Numis said in a note. They cut their rating on the stock to "reduce" from "hold". (Reporting by Alistair Smout, Editing by Jane Merriman and Susan Fenton)