Travel giant Tui has said it remains on track for a double-digit-percentage rise in annual earnings despite the long summer heatwave denting demand across the UK and Europe.

The group confirmed that the unusually hot summer and airline disruption over the peak months had made trading "more challenging".

It also revealed a higher-than-expected currency exchange hit of around 70 million euros (£62.4 million).

But boss Friedrich Joussen said the group was sticking to its forecast for growth of at least 10% in underlying earnings over the year to September 30.

The heatwave played havoc with the late bookings market, impacting a raft of holiday firms and airlines, with Thomas Cook warning over profits earlier this week due to the impact of the hot weather.

Mr Joussen said: "Having continued to expand our hotel and cruise offer, occupancies and yields remain high, and the number of customers purchasing holidays from us has grown in all major markets, even with the sustained period of hot weather in Northern Europe this summer.

"This demonstrates the strength and resilience of demand for our holiday experiences, although, as previously stated, the hot weather has limited our ability to outperform."

He added that trading for future seasons was in line with its expectations, albeit at an early stage, with around a third of its winter season programme sold an customer numbers up 2%.

Tui said group-wide sales and marketing revenues rose 5% for the summer season, with customer numbers up 4% and average selling prices up 1%.

The tour operator is seeing easing demand for holidays in Spain after a boom in recent years, but said it was benefiting from a recovery in bookings to Turkey and North Africa.

Greece is also becoming more popular, as are smaller destinations such as Bulgaria.

Shares in Tui rose 2.5%, having tumbled last month when the company revealed an 18% drop in third-quarter earnings and said summer bookings were being held back by the heatwave.

Paul Hickman, analyst at Edison Investment Research, said Tui's latest update had reassured worried investors.

"Although some observers were expecting Tui to have been impacted by the issue flagged by Thomas Cook on Monday of hot weather impacting the late booking market, Tui has actually avoided the worst of that," he said.