British travel group Thomas Cook today issued its third profit warning in less than a year.

The company's shares tumbled to a six and a half low as it said discounting and higher fuel and hotel costs would hurt it during the peak summer season. 

Thomas Cook said it had received multiple bids for its airline unit,.

But his news was overshadowed by what chief executive Peter Fankhauser called a "difficult trading environment" despite a delay to Britain's exit from the European Union. 

"With a lot of holidays left to sell across the market, there are high levels of discounting at this early stage of the season. This is putting further pressure on margins," Fankhauser told reporters.

He added that a delay to Brexit from March 29 until October had brought no respite. 

"There's no doubt that we have had a decline in consumer confidence during this whole Brexit phase in the run-up to March, but we have seen no material change to booking patterns in recent weeks since the delay to Brexit was announced," he added. 

Thomas Cook warned that second-half underlying earnings before interest and tax would be below the same period last year and added it had agreed a £300m bank facility to provide more liquidity for the 2019/20 winter season. 

Shares had fallen as much as 23% at one stage today to their lowest level since November 2012, taking the value of the company below £300m.

The oldest travel company in the world stumbled badly last year when a heatwave in northern Europe deterred holiday makers from booking lucrative last minute deals, leading to two major profit warnings and talk of a need to raise funds. 

Thomas Cook said the outlook for bookings across Europe was lower than last year. 

Germany and Sweden were impacted by economic weakness, with the latter also seeing a growing environmental movement against air travel. 

The firm said that it saw stronger demand for travel to Turkey, Egypt and Tunisia but hotel costs were rising.

Thomas Cook wants to sell its airline business, which includes German holiday carrier Condor, to cut debt and allow it to invest in its core holiday operations. 

Net debt rose to £1.25 billion by the end of March from £886m a year earlier. 

Thomas Cook said it had received multiple bids for all and part of a business which consists of Condor, as well as British, Scandinavian and Spanish divisions. Its airline unit is faring much better than its tour operator business. 

Lufthansa has said it wants to buy Condor with an option to acquire the remaining airlines, while Virgin Atlantic is also reportedly interested in part of the business. 

The company said it made an underlying loss before interest and tax of £245m in the six months to March 31, compared with a loss of £65m in the same time a year earlier. 

Thomas Cook also took an impairment charge of £1.1 billion relating to a 2007 merger with British package-holiday company MyTravel.